(CNN) With little in the way of constructive negotiations and no end to the partial government shutdown in sight, pressure builds, particularly on Republican senators who are nervous with President Trump's take-the-wall-or-else tactic.

At least three Republican senators, all up for reelection, have suggested they would break with Trump and support appropriations bills that do not include funding for a wall.

That's far short of the 13 it would require to overcome a filibuster and very far short of the 20 Republican senators it would require to overcome a presidential veto and reopen the government without him.

Here's what some key Republicans have said: