Greg,
	There is also the possibility, that the anti-messiah, the antichrist, may attempt to deceive Israel regarding Daniel 9:27.
He may, in an attempt to convince Israel, that he is the Messiah, and to "prove it", he will offer his own confirmation of the covenant.
He may say that in confirmation of the covenant of the law, Israel should be allowed to rebuild their temple, and to restart the animal sacrifices.
But at some point he will go into that temple and show himself to be God.
At that point he will persecute, and attempt to destroy, those of Israel who will not worship him.
That time of persecution will last 3½ years.
So during that same period of time, the time of Jacob's trouble, the real Messiah, Jesus, will be preparing the remnant of Israel for his return.
While the anti-messiah will simultaneously be attempting to destroy them.