From today's WSJ:
Senate Republicans Push Back on Trump’s National Emergency Talk.
GOP lawmakers worry that a move by the president to shift funds for a border wall could backfire.


In part:

WASHINGTON—President Trump’s repeated warnings that he is prepared to declare a national emergency to build a border wall, which he is likely to renew in his State of the Union address Tuesday, are stirring up increasing angst among congressional Republicans.

Senate Republicans, who are typically more muted in their criticisms of the president, have been unusually candid in pushing back against such a move, which would likely divide them on any coming vote. The five-week partial government shutdown that ended last month left many frustrated with the White House and Mr. Trump’s willingness to circumvent Congress to build a wall along the border with Mexico.

Mr. Trump has said that if lawmakers don’t reach a deal that satisfies his demands to build a wall, he may declare a national emergency. That could potentially enable him to shift either military construction or U.S. Army Corps of Engineers funding to construction of the wall, although such a move is certain to be challenged in court.

Many Senate Republicans are concerned about the precedent that could set, enabling a future Democratic president to declare a national emergency to address a liberal priority, such as combating climate change. Libertarian-leaning Republicans have been warning about such ramifications for several weeks.

“There have been lots of concerns expressed about that approach, which have been conveyed by many of our members directly to the president,” Senate Majority Whip John Thune (R., S.D.) said Tuesday, adding that those issues include “the precedent it creates for a future Democrat president to find lots of reasons to declare an emergency, the questions about separation of power and checks and balances and everything else.”