Of course they can.
Read the scripture where Jesus explains the parable of the sower and find this, the first 3 verses:
Luke 8:11-15 King James Version (KJV)
"11 Now the parable is this: The seed is the word of God.
12 Those by the way side are they that hear; then cometh the devil, and taketh away the word out of their hearts, lest they should believe and be saved.
13 They on the rock are they, which, when they hear, receive the word with joy; and these have no root, which for a while believe, and in time of temptation fall away."
We all know the seed is Gods word, and if you look closely at the second verse, you'll see they "heard" the word but the devil snatched it away before they had a chance to receive it, and be saved.
But the third verse, they heard and "believed" or were clearly saved for awhile, but were temped to the point they would "fall away" from their salvation.
Now the first thing those that choose no to believe that will do (and this or other parts of this post, are not necessarily directed at you, ml5363) is attack the fact that they were saved at all. That is of course clear to me, and others, but they will try to confuse that one issue, however, if they didn't "fall away" from salvation, what did they fall away from?
Then there is this comment.
James 5:19-20 New International Version (NIV)
19 My brothers and sisters, if one of you should wander from the truth and someone should bring that person back, 20 remember this: Whoever turns a sinner from the error of their way will save them from death and cover over a multitude of sins.
Those people are "brothers and sisters", or saved people, and the fallen in this case is "one of you" or were saved like the rest of them. Now, if that saved person was "brought back" they had to have been gone from something, and in context, that can only have been their salvation.
Now I realize some of you are thinking "Well Duh, the meanings there is obvious" but I tell you, once some get on the kick they are saved forever no matter what they do, they don't take kindly to someone trying to convince them otherwise. They will fight the obvious truth tooth and nail, and will choose not to believe what was just quoted from the Bible They will throw all kinds of nonsense at the clear and simple truth. That's the reason I explain what is obvious to most, so a child can understand it.
They badly want to believe the very selfish, "We can do as we like and still go to heaven", because it's more fun then being obedient to God. At least that's been my experience with OSASr's, some of the meanest most ungodly selfish people I've had the displeasure of being around... and all because they can, at least in their mind.