In any community there are exactly as many of the Christian elect as God has decreed.
Indeed!
If there is a reduction in the number who are counted as Christians, that is a reduction in the visible church only. Satan and his minions combined with every anti-Christ throughout history have never snatched even one of His elect. ALL given by the Father to the Son SHALL come to the Son and be raised up on the last day.
“All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out. All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out. For I came down from heaven, not to do mine own will, but the will of him that sent me. And this is the Father’s will which hath sent me, that of all which he hath given me I should lose nothing, but should raise it up again at the last day.”
—John 6:37-39)