This story was originally published on February 12. It has been updated to reflect reporting that President Donald Trump intends to declare a national emergency after signing the border security bill.

Washington (CNN) President Donald Trump has signaled to lawmakers he will sign the compromise border security legislation in conjunction with plans to declare national emergency to secure funding for a border wall.

Doing so could set off a chain of events on Capitol Hill that risks splitting the Republican conference, undercutting other parts of Trump's agenda and likely opening the administration's actions to legal challenges. It may also provide a clarifying moment that Republicans on the Hill have managed to avoid since Trump took office -- casting an up or down vote on whether to build the full-scale wall Trump desires.

According to federal law, Congress can rescind a presidential emergency declaration by passing a joint resolution. In the likely event that such a bill would be vetoed by the President, Congress could then override it with a two-thirds majority in the Senate and the House.

The danger to congressional Republicans isn't having to overcome a presidential veto, but in having to vote on the resolution itself. Any such measure would be considered privileged -- if, for example, the House passed it then the Senate would be required by law to vote on the measure within 18 days. Senate Majority Leader Mitch McConnell would be powerless to stop a floor vote.

Republicans have been looking for a way to avoid that altogether. For weeks, GOP leaders in the Senate have publicly tried to dissuade Trump from declaring a national emergency. Last month, even before the end of the 35-day government shutdown, one GOP senator approached the White House counsel's office to encourage the President to embrace a narrower executive action to fund a border wall without declaring a national emergency, according to a person familiar with the conversation. That would limit Democrats' ability to block Trump's actions, and also the amount of federal dollars he could use to start building the wall.

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