House Republicans' decision to schedule a Thursday vote on a bill that reforms and replaces the Affordable Care Act suggests they are now willing to roll the dice even though the final outcome is far from certain.

Tonight's decision comes after the party has spent weeks tweaking the bill to attract wavering members. Combine the risk involved with the level of public sausage-making and a simple question arises: Why?

After all, it's clear that threading the needle between the House Freedom Caucus on the ideological right and the Tuesday Group in the center is a perilous proposition. Republicans have already swung and missed twice. Even with the current momentum behind Michigan Rep. Fred Upton's amendment to fund state-based high-risk pools as a fix for the decision to waive the federal mandate on covering people with pre-existing conditions, it's going to be a very, very close vote -- if there is a vote at all.

So, again, why? Especially since the bill may never go anywhere in the Senate or be amended beyond belief. Those two possibilities make Democrats convinced that the worst thing House Republicans can do is vote on this health care bill. (Democrats believe a vote is the best thing for their own political fortunes.) They liken it to their own disastrous decision in 2009 to vote on a cap and trade bill that quickly died in the Senate and was subsequently used against Democratic members in swing districts to cast them as extreme liberals beholden to the national party, not their constituents.

I've talked to a handful of Republican members and senior campaign staffers about just that question. While they recognize voting on a bill with an uncertain legislative future is a risk, they think the bigger risk is not passing anything at all. There are two main reasons behind that thinking:

1. Repealing and replacing Obamacare -- which is not exactly what they will be doing, but whatever -- was the issue Republicans built their entire message around over the last 7+ years. The promise they made to their base was that if they were voted into power, the bill would be gone. It's on the back of that message that they won control of the House in 2010 and the Senate in 2014. It played a major role in pushing Trump over the top against Hillary Clinton too.

Given the centrality of health care to everything Republicans have talked about over the last seven years, to simply throw up their hands and give up is unthinkable. GOP strategists believe deeply that to walk away from health care would cause a revolt -- or at least a major enthusiasm dip -- within their base. And, with the Democratic base fired up beyond belief to send a message to Trump, the 2018 midterms could be a total disaster.

1. The country is looking to Republicans to show they can actually govern. Not just protest the policies of the Obama Administration, but actually govern. At the moment -- and it is, granted, quite early -- the scorecard doesn't look very good. Tax reform is a long process that has only just begun. Building Trump's much-promised border wall will be a long and arduous process -- if it happens at all.

Republican members of Congress need something tangible to take to their constituents come August recess. They need to be able to point to a major piece of legislation that they promised they would deliver and show that they made good on their end of the bargain. (Obviously this argument gets complicated if the Senate either doesn't act on a House-passed measure or amends it heavily.) Health care, which is of critical importance to the Republican base (see above), would have that effect, they believe.

That's why Republicans are pushing all their chips into the middle on this. The only other option is to go bust.