“We heard last week what he would sign. That’s no longer what he would sign,” he added, making reference to signals from the White House that Trump would sign a clean stop-gap measure keeping government funded over Christmas.
Yep, that's until the screws were tightened down by border wall supporters and folks who were holding the President to his past promise not to sign another DHS funding bill without funding for a wall! Trump withered under the fire he was getting! His only option under such immense pressure was to relent and flip.