WASHINGTON — Just hours before a midnight deadline, a bitterly divided Congress approved a stopgap spending bill Wednesday to keep the federal government open — but with no assurance there won’t be yet anothershutdown showdown in December.

Democrats helped beleaguered House Republican leaders pass the measure by 277-151 — a lopsided vote shrouding deep disagreements within the GOP — after the Senate approved it by a 78-20 tally earlier in the day. President Barack Obama signed the bill Wednesday evening, but not without White House carping.

“The American people deserve far better than last-minute, short-term legislating,” said spokesman Josh Earnest in pressing for a broader, longer-lasting budget deal.

Approval of such stopgap measures used to be routine, but debate this year exposed acrimonious divisions between pragmatic Republicans such as House Speaker John Boehner and more junior lawmakers in the party’s tea party wing who are less inclined to compromise. The tea partyers had demanded that the must-pass measure be used to punish Planned Parenthood, stripping it of federal money because of its practice of supplying tissue from aborted fetuses for scientific research.

House Republicans opposed the measure by a clear margin, but Democratic support was unanimous.

The legislation finances the government through Dec. 11, providing 10 weeks to negotiate a more wide-ranging budget deal that would carry past the 2016 presidential election. But the talks promise to be difficult, and success is not assured.

Boehner is resigning from Congress at the end of October, a decision he announced last week after informing Republicans he would not risk a government shutdown over Planned Parenthood.

A similar fight over implementing Obama’s health care law sparked a 16-day shutdown two years ago that Boehner, Senate Majority Leader Mitch McConnell of Kentucky and other top Republicans did not want to repeat in election season. McConnell is seeking to protect embattled incumbents in Democratic-leaning states such as Wisconsin and Pennsylvania, while some GOP conservatives are more apt to use the battle to appeal to the party’s core voters on the right.

“Today was a win for the Washington cartel, and another setback for the American people,” said Sen. Ted Cruz, R-Texas, who is using combat with Washington GOP leaders to help define his presidential campaign. “Republican leadership chose to abandon its constitutional power of the purse and to fund 100 percent of President Obama’s failed agenda.”