Well, to answer that we 1st need to answer what is a Christian?
Perhaps the simplest definition is "Someone who follows Jesus".
So, on that basis are Roman Catholics Christians?
Well, you'd have to say: Yes.
This is because you could be a historian and study the effect Jesus had on the nations through the centuries and in doing this be called a "follower" of Jesus.
So that: Yes, in that sense many Roman Catholics are Christians.
For evangelicals, a better definition perhaps would be someone who has come to know Jesus personally and thus know Him as their own Lord and Saviour.
So, on that basis are Roman Catholics Christians?
Well, on that basis you'd have to say: Yes and No.
There are those who are brought up Romans Catholics (RC) who come to know Jesus in this way and many who never get to hear you can come to know Jesus in this personal way.
The Alpha course has been used by some Roman Catholic churches in no less a way than some evangelical churches and as such has promoted the knowledge and experience of Jesus in a personal way for the individual person attending the church services. But many have not, and it is not part and parcel of the overall RC manner of reaching out, so that many RC do not know you can or that it is needful, to have a personal encounter and relationship with Jesus. Instead the RC church is emphasised as the place and entity to be saved through.
So it can be seen that Yes and No are appropriate.
Paul wrote "whoever calls on the name of the Lord shall be saved." (Romans 10:13). But whilst some are encouraged to do this for themselves (e.g. as per the Alpha course) many are not and, instead, encouraged to see the church as their mediators and that via the priest. Paul wrote about a mediator:
. . . God our Saviour, who desires all men to be saved and to come to the knowledge of the truth. . .
1 Timothy 2:3-4
And what truth would that be?
. . . there is one God and one Mediator between God and men, the Man Christ Jesus. . .
1 Timothy 2:4-5
There we have it. The bible is explicit that the only person between God and men whom God sees as Mediator is Jesus. So it is imperative for any calling on the name of the Lord to be done personally. No priest, or any group of people claiming to be, Jesus is your only mediator with God.
How else do many Christians define the act of becoming a Christian?
Many claim you need to be born again and thereby call themselves, or are known as, "Born again Christians". This is a term used to describe the moment in time when they did make a personal commitment to follow Jesus.
So, on that basis is an RC Christian?
Well, if being born again is the same as having a personal relationship with Jesus, then the answer has to be the same as above: yes and no: some are and some are not.
But, if we understand that being born again is not the act of becoming a Christian, but in fact an event that precedes it, and is not a wholly conscious experience, then I would have to say, yes there are many RC who are born again.
Jesus said - using the phase "born of the Spirit" in the same passage that he mentions being "born again", and thereby speaking of the same event - Jesus said it is not a wholly conscious matter:
The wind blows where it wishes, and you hear the sound of it, but cannot tell where it comes from and where it goes. So is everyone who is born of the Spirit.
More than that, Jesus is explicit this is something that happens before one can see, let alone enter the kingdom of God.
. . . unless one is born again, he cannot see the kingdom of God.
So this act of being born again is not limited - in truth - to knowing certain things about Jesus or the act of conscious conversion to Christianity. It can indeed - by reading this clarification - be seen as the experience of someone born deaf and blind or, anyone who has never heard about Jesus. I explain all this in more detail in my chapter entitled The meaning of born again in my book Will there be Non-Christians in heaven?
This of course brings into play the question "Do only Christians get to heaven?" Well, if a deaf and blind person can get to heaven and babies who die not hearing about Jesus can, then I would have to say an emphatic: No. It is not just those recognised as Christians who get to heaven.
So in that sense, yes there is some RC who will make it.
And if being born again as just mentioned is not the act of becoming a Christian - not consciously having Jesus as your only Mediator - then yes, many RC are as safe as Christians, but - and it is a big but - have no assurance, until they go on to make that personal call on Him to save them and thus become a Christian. Baptism then should follow as a witness to that act.
A church definition in regards to salvation
The church in the bible is the body of believers, so here I am using the term church to identify the bible view of the place of regular worship or of teaching: In regards to salvation, in view of the above truths of the bible, a church is one that can give assurance of salvation by presenting the fact that Jesus is the sole Mediator and that there is a personal need to call on Him: It is those who practise this in the gathering - those who are of this like relationship with Jesus - who can call themselves a church. A church that claims it takes the place of the sole Mediator is not a church: any church to be Christian and biblical needs to point to Jesus as the only one to call on and that personally. But, as mentioned, as the Alpha course is used by some RC, these do practise the truth in opposition to the general norm among the RC.
What else can be seen as contrary to the bible in the RC?
Well, Paul made clear that to be a church leader you need to be the husband of one wife, but the RC advocate not to be married at all.
A bishop then must be blameless, the husband of one wife . . .
1 Timothy 3:2
In fact, Paul claims that it is deceiving spirits that teach not to marry.
. . . some will depart from the faith, giving heed to deceiving spirits and doctrines of demons . . . forbidding to marry . . .
1 Timothy 4:1-3
There may be a place for voluntary celibacy, but not as the rule for the majority. To make the exception the rule is deception. It is when so many are naturally out of place whilst in their leadership positions that it is evident there will be those who fall leading to secret affairs and hidden acts of evil abuse among children.
For many RC there is the worship of Mary, Jesus' mother. Now, if Jesus is the mediator and he himself taught not to hold Mary higher than any other person who does God's will then, to go further than that is against Jesus' teaching, is it not?
But He answered and said to them, "My mother and My brothers are these who hear the word of God and do it."
Those who hear the word of God and do it Jesus said are held in the same esteem as Jesus' mother and the rest of his family. Any more than that is idolatry.
Part of the role of a priest in the RC is to make Jesus' sacrifice real again every time there is the mass as they call it (communion or the Eucharist as named elsewhere). In the RC it is not a representation of the event of Jesus' sacrifice on the cross, but an actual act of sacrifice again every time the mass is practised. This is in contrast to the truth here:
. . . we have been sanctified through the offering of the body of Jesus Christ once for all.
The offering is the sacrifice. The sacrifice mentioned is the body of Jesus on the cross. It is explicit by this "once" that it is final and complete. It is not repeatable. The institution Jesus made was of a remembrance event; no more. It is not a new sacrifice every time. This is why in the sudden recognition of the truth in this passage one former RC priest Franco Maggioto, whilst in charge over other priests at the time and during a mass service, exclaimed at that moment of realisation "We are sacked! We are sacked!" - He has a great testimony.
Jesus instituted that both the bread and the wine be used by all his followers:
He took the cup, and gave thanks, and gave it to them, saying, "Drink from it, all of you. For this is My blood of the new covenant, which is shed for many for the remission of sins."
It is not just the bread Paul confirms but the bread and the wine:
. . . as often as you eat this bread and drink this cup, you proclaim the Lord's death till He comes.
1 Corinthians 11:26
In the RC only priests partake of the wine. Not "all of you" as Jesus stated.
Baptism (also known as christening) of infants
Baptism is to be practised as commanded for all believers, but what is different from the bible in a range of churches including the RC is that babies are baptised. There are no examples of babies being baptised in the bible and all mentions of the act are either explicit or implied that it is to follow a conversion or for a disciple: someone who has consciously decided to follow Jesus. So that you get clear statements like this one from Peter:
Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit.
It is after repentance that baptisms happen.
Babies cannot repent since they are not mentally conscious to do right or wrong. Jesus was dedicated as a baby; not baptised as a baby, so the practise of dedication is good, but infant baptism is foreign to the bible. And, since Jesus was baptised this event itself also speaks in that the practise also known as the sacrament does not save anyone as Jesus did not need saving.
So, what is the conclusion of the matter?
It is that many RC do follow Jesus. And many consciously do so in a personal relationship with Him as their mediator and witness to Jesus being the way, the truth and the life. Also many RC are baptised in the Holy Spirit and, just as this was a testimony for the Jewish believers in Jesus to God's acceptance in Acts (10:45-46) of Gentiles, so it is now a witness of RC who speak in tongues and prophecy, etc... Not forgetting of course that these 'gifts' and signs are not what saves a person, they're just a demo of their "receiv[-ing] the Holy Spirit"(as Paul put it in Acts 19:1-6) and that following their belief in Jesus personally.
However, until the main RC doctrine reflects that Jesus is the only Mediator and the sacraments do not convey salvation, but only a repentant heart and a calling on Jesus personally can do that for assurance, then the RC is not a safe place to abide and remain in. And this is why there are many RC who are not Christian.
And, as exemplified in other matters - just as with many other 'churches' too - much dogma and practice is not of the bible. For example it is a shame that Franco as an ex-priest mentioned above, then went on to join a Reformed church: having left a set of deception he then entered another.
In reformed teaching God is said to have picked all who go to heaven and all who go to hell already and this is also known as Calvinism. There are about 70 million in reformed related churches in the world. And there are an estimated 1.1 billion RC (about half of all "Christians" today).
You may note that I stated "the RC is not a safe place to abide and remain in", but whether due to the RC or any other "Christian" group, the opportunity to know Jesus at all may be for some only by the fact of the presence of that "church" in its midst. A good example of that would be Dr Nagai of Nagasaki who with no other Christian witness than the RC and out of a devout Shinto background became a Christian due to that RC presence giving him access to the truth. Dr Nagai went on to be a champion for forgiveness whilst a hero-survivor of the last atomic bomb to fall in conflict in 1945.
I mentioned that salvation is not limited to being a Christian or else no one born deaf and blind would ever make it. This is also true for any mentally disabled to communicate more than on basic themes, nor any babies and little children. I mentioned you can be born again long before you become a conscious follower of Jesus and thus go on to be named fully a Christian. I also said there is no assurance of salvation according to the bible without knowing Jesus personally as your Lord and saviour: having called on him yourself. But, let's not forget that even though Paul taught:
. . . if you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved . . .
He also went on to say, how can they believe unless they hear; and how can they hear unless someone tells them, but then he says have they [really] not heard, yes they have, because Creation itself speaks to everyone:
But I say, have they not heard? Yes indeed: "Their sound has gone out to all the earth, and their words to the ends of the world."
This is a quote from the Psalms by Paul.
The heavens declare the glory of God; and the firmament shows His handiwork. Day unto day utters speech, and night unto night reveals knowledge. There is no speech nor language where their voice is not heard. Their line has gone out through all the earth, and their words to the end of the world.
So that there are those born again who have responded positively to the little revelation they have received, but then go on to become known as Christians once they hear that Jesus is the only mediator. I recall the story of Ladonna Elliott who was teaching us students at Christian Life College in London where I went 3 evenings a week in 1984 and 85. Ladonna is daughter of the Principal Elmer Darnall and related what happened when as a YWAM missionary she travelled in Afghanistan in the days before the Russian occupation. She met a man whom she proceeded to share Jesus with. As she did so his face lit up and he became more and more excited with what he heard and exclaimed something like "That's him! That's him!" He then shared with Ladonna how he had come to believe in Jesus but did not know that was his name, nor what he had done on the cross.
If you'd like to call on the Lord to be your saviour personally there is an example of a prayer you can make at the end of my chapter A Word About Evangelism from my book Will there be Non-Christians in heaven?
Are Roman Catholics Christians? Answer: Some.