If impeachment fails - as it probably would - the Constitution would be weakened to the point of collapse.
The Democrats would be in a corner. They would have to choose between defending a President who was obviously ignoring the Constitution, and defending the Constitution which (a) inconveniences them and their president, and (b) they’re not really that into anyway.
Which choice do you think they would make?
Pretty much the same thing happened when they impeached Samuel Chase, the one and only Supreme Court Justice ever to be impeached.
He was not removed, and no other SC Justice was ever impeached again, leaving the Supreme Court unchecked ever since.