They went ahead and did it. House Republicans pushed through a stopgap spending bill on Friday that would keep the government from shutting down on Oct. 1, but includes a provision that would defund ObamaCare.

The 230-189, party-line vote set up a showdown with Democrats, who control the Senate, just 10 days before federal agencies run out of money. The Senate is expected to strip out the part about the Affordable Care Act and send it back. If neither side bends, much of the government will have to shut down starting Oct. 1.

Many people, including lawmakers and political strategists on the left and right alike, have warned that passing the spending bill as written was an exceedingly bad idea. One reason is that it rescues President Obama just when opposition from within his own party had people saying his presidency was in trouble. Indeed, there are plenty of reasons why this bill is likely to backfire on Republicans. Here are four of them:

1. Conservatives can't win this fight
The bill now goes to the Senate, where it "stands zero chance of winning passage," says Sean Sullivan at The Washington Post. "None. Zilch." Essentially, that means it raises the threat of a potentially calamitous shutdown for nothing, say critics of the tactic, including Republican strategy guru Karl Rove. Obama has already threatened to veto this spending bill, but he'll never have to because it will never reach his desk. And news flash: "ObamaCare implementation will likely continue even if the government shuts down," says Dylan Scott at Talking Points Memo, because the administration dips into discretionary funds to pay for elements, like premium tax credits, that start Oct. 1.

GOP leaders want to continue the fight in a few weeks, say Jake Sherman and John Bresnahan at Politico, when Congress has to raise the $16.7 trillion debt ceiling or run short of money to pay its bills. GOP leaders want to trade a one-year extension of the debt ceiling for a one-year delay of ObamaCare, the Politico writers say, but Obama says there is no way he will negotiate on whether the U.S. will pay its debts, because defaulting would trigger a global financial crisis.

2. The public will blame the GOP if the government shuts down
The last time a partisan showdown shut down the government was 17 years ago — when Bill Clinton and Newt Gingrich stared each other down, and neither blinked. That fiasco resulted in a backlash against the GOP, with the party picking up a couple of Senate seats in the next election, but losing ground in the House and many states. Oh, and Clinton won re-election.

Polls suggest that many Americans are wary of ObamaCare, but they like the idea of a shutdown even less, says Tom Cohen at CNN, and if one comes they would blame Republicans... again.

3. Time is not on the GOP's side
"The GOP gamble is premised on ObamaCare's continuing unpopularity," says Greg Sargent at The Washington Post. Fair enough, he says, but polls show there is a "substantial overlap between public disapproval of the law and self-professed public ignorance about it — which could change as people experience it firsthand."

If Americans warm to the health-care law once they finally get to experience what it does, Sargent says, Republicans will find it difficult to justify how they let a radical minority in their ranks bring the government to its knees in an attempt to stop it.

4. The move makes Boehner look weak
House Democrats are hailing the spending bill as a sign that the House GOP has been officially taken over by its Tea Party faction, notes Sabrina Siddiqui at The Huffington Post. House Speaker John Boehner and Majority Leader Eric Cantor wanted to avoid the threat of a shutdown at all costs, but they couldn't muster enough votes to pass a bill that didn't go after ObamaCare.

"For Mr. Boehner, the announcement Wednesday was a humbling moment, and possibly a defining one," says Jonathan Weisman at The New York Times. "Since the Tea Party wave swept Republicans to power in 2010, the beleaguered speaker has often found himself at odds with the most conservative wing of his conference." Well, Weisman says, by pushing through this bill and threatening the nation with a potentially catastrophic shutdown he doesn't want, Boehner has very publicly "waved the white flag," leaving House Republicans with a weakened leader.