WASHINGTON – The White House and Republican senators sought compromise Tuesday on limiting future presidents' powers to unilaterally declare national emergencies, as chances improved that President Donald Trump might avoid a long-expected rejection by Congress of his effort to divert billions more for building barriers along the Mexican border. As a Thursday showdown vote in the Senate neared, GOP Sens. Mike Lee of Utah, Thom Tillis of North Carolina and others were talking with the White House about related legislation that would curb the ability of future presidents to declare national emergencies. If Trump would commit to signing a bill...