(CNN) Some Senate Republicans will join with Democrats on Thursday to rebuke President Donald Trump on the central pledge of his presidential campaign, the animating issue of his presidency and the defining action of the last few months.

It's not a question of if enough Republicans will support a Democratic resolution to terminate the President's national emergency declaration to build a wall along the US border with Mexico. It's a question of how many.

Bottom line: The last-ditch effort to find a way to assuage concerns of Senate Republicans fell apart Wednesday, and the resolution will pass. Trump will be forced to veto the resolution -- the first veto of his presidency.

The bigger picture: For the second time in two days, Republican senators will join with Democrats to support a measure the White House opposes -- first on Wednesday to end military support for Saudi Arabia in the civil war in Yemen, followed by Thursday's vote to terminate the national emergency.

There are common threads here, from views of executive branch overreach to an administration that repeatedly declined -- or couldn't -- provide the information GOP senators explicitly requested as they made up their minds on these votes.

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