Agreed. Politicians are to blame for the current immigration mess and their only escape exit is to jump with both feet into unification of Canada/America/Mexico.
If you can't fix a problem, turn that problem into a goal.
That was their goal from the start and they have been using mass immigration as the means to achieve it. When the American public no longer feels like their country is their own then they won't object to having it merged with Mexico and Canada.
The only fly in the ointment is that the public may be catching on and rising up to strike back in anger. We'll see at election time.