Senate Majority Leader Mitch McConnell (R-Ky.). (Melina Mara/The Washington Post)

THE COMING days will determine if politicians can strike any sort of deal on immigration. If they do not, hundreds of thousands of “dreamers” will be condemned to deportation or a life on the margins of American society.

So far, Senate Majority Leader Mitch McConnell (R-Ky.) has done nothing to suggest he is intent on forging a deal that would protect dreamers, young immigrants educated and reared in the United States after they were brought into the country as children. To the contrary, Mr. McConnell gives every sign of maneuvering for political advantage, with an eye to maintaining the Republicans’ tissue-thin Senate majority in this fall’s elections.

Coupled with President Trump’s statement Wednesday doubling down on his own hard-line demands for cuts to legal immigration, what emerges is a picture of a GOP leadership that would rather play politics with the dreamers than find a realistic compromise.

We hope we are wrong about that. An emerging bipartisan plan offers an alternative and a way around the impasse Mr. Trump himself created by announcing his intention to rescind Deferred Action for Childhood Arrivals, the Obama-era policy that protects dreamers.

As his opening gambit on immigration Tuesday, Mr. McConnell pushed a bill to punish so-called sanctuary cities that refuse to cooperate with federal deportation officials, a measure that has nothing to do with dreamers, nor even with border security or a wall along the boundary with Mexico. Rather, it was a ploy designed to set a trap for swing-state Democrats who are loath equally to alienate base voters who oppose enabling deportations and to appear soft on criminals.

Mr. McConnell then gave his full support to the president’s statement insisting on the “four pillars” of his latest immigration approach, which included closing the country’s borders to hundreds of thousands of immigrants annually who enter the country legally to join relatives who are citizens and permanent residents of the United States. That trade-off as the price for protecting dreamers — a huge cut to legal immigration, on top of the $25 billion Mr. Trump is demanding for his border wall — is a nonstarter for Senate Democrats. Mr. McConnell knows that; nevertheless, he persists in backing an unworkable plan.

The test will come after Mr. Trump’s plan, incorporated in a Republican bill introduced by Sen. Charles E. Grassley (R-Iowa), is defeated on the Senate floor, as it most likely will be. Will Mr. McConnell then join in promoting legislation that could attract the necessary 60 votes?

A narrower plan, which would extend a path to citizenship for about 1.8 million dreamers (though not their parents) in return for $25 billion for the president’s border wall, has been embraced by a bipartisan group of senators calling themselves the Common Sense Coalition. Theirs is a plausible recipe for a real solution that would test Mr. Trump’s declaration last month that he would sign any legislation passed by Congress. We hope the majority leader chooses governing over cynicism.