(CNN) President Donald Trump will sign a bill to avert another government shutdown, but also issue a national emergency declaration to build a wall on the US southern border, according to Senate Majority Leader Mitch McConnell, replacing lawmakers' most pressing problem with one that strikes at their power to spend money.

For his first two years in office, Trump enjoyed Republican control of Congress and was still unable to get what he wanted on border security, his signature campaign issue. The likelihood of that dropped even further when Democrats won control of the House of Representatives in the November elections.

Trump's first reaction to that result was to fight Congress, shutting down parts of the government from December 22 until January 25. Now, it appears he'll go around it.

Republican and Democratic lawmakers reacted to McConnell's announcement with alarm.

"I think it's a mistake," said Sen. Susan Collins, Republican of Maine. "The National Emergencies Act was contemplated to apply to natural disasters or catastrophic events such as the attacks on our country on 9/11. For the President to use it to re-purpose billions of dollars, that Congress has appropriated for other purposes that has previously signed into law, strikes me as undermining the appropriations process, the will of Congress and being of dubious constitutionality."

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