Republicans are grappling with the possibility they will soon have to work with the Democrats as a deadline to raise the debt ceiling threatens to fray party unity.

Washington has until the late spring or summer to raise the borrowing limit past its $36 trillion cap, setting up a test with economy-reverberating consequences for Republicans. Despite having unified control of Washington, they would have to convince dozens of fiscal hawks to hold their nose and vote “yes” to go it alone.