Ted Cruz's plan to end Obamacare is moving full steam ahead, after Friday's House vote approving a funding bill that leaves out money for the healthcare plan. Cruz has promised to do anything in his power to get the measure through the Senate, including filibustering. Unfortunately for Cruz (and his conservative backers), there are (at least) four problems with that effort, including, for starters:

1. How do you pass a bill that you're filibustering?

Filibusters, the once-uncommon procedural device senators can use to force a supermajority vote on an issue, are a spectacular tool for halting legislation. It's part of the reason that this Congress has been so unproductive; the Republican minority in the Senate has been using the filibuster to impede the Democratic majority's agenda.

But filibusters are a very bad tool for passing legislation. Here's how one Senate aide described it to Talking Points Memo: "You can't pass defund Obamacare legislation by filibustering defund Obamacare legislation." Which is true! Earlier this month, Rand Paul noted the physical constraints of the procedure. But even if Cruz suddenly develops the super-human ability to filibuster endlessly, what then? While he's on the Senate floor yakking away, the bill isn't getting any closer to passing. Yes, it brings the government to a halt, but it doesn't pass any legislation defunding Obamacare. (More on this in a bit.)

2. Passing a bill needs 51 votes.

Even assuming that Senate Democrats wouldn't themselves filibuster the House bill, requiring their own 60 unattainable votes to be overcome, Cruz still needs at least 51. (His plan won't work with 50 votes, of course; tie-breaker Joe Biden probably would vote no.)

So where do those votes come from? There are 45 Republicans in the Senate, so Cruz needs at least six Democrats to join him. Well, seven, actually, since Republican Ron Johnson of Wisconsin opposes Cruz's effort.

We won't belabor the point; the votes do not exist. Cruz's ostensible theory is that the Democrats, panicked about a shutdown threat, will cave. That's optimistic in the way a kid jumping on a trampoline and hoping to reach the moon is optimistic. But for the sake of argument, let's say it works. That moderate Dems are somehow convinced of the plan. Because that brings us to fatal flaw three …

3. The president won't sign it.

He won't. We've gone over this so many times by now, and it will not happen. Obamacare is the president's signature legislation. It has his name in it. He won't sign a bill eliminating it.

Remember, in this scenario Cruz has cowed seven Democratic senators into supporting his plan. What's the likely threat he would use to do so? Reelection, one assumes, focusing on senators like North Dakota's Heidi Heitkamp, who represent predominately Republican states. But Barack Obama is not worried about reelection. Earlier this summer, we noted that his push to ensure the success of Obamacare is his last major campaign, and it is one he will not sign away because he is afraid of Ted Cruz.

4. A shutdown won't stop Obamacare.

And then there's the last flaw. Conservatives are aiming for a shutdown in part because they'd rather have government come to a halt than see Obamacare go into effect. Except that the shutdown will not prevent Obamacare from going into effect — as has been public knowledge for months.

Senator Tom Coburn from Oklahoma asked the Congressional Research Service to assess the effect of a shutdown on Obamacare back in July. The non-partisan body's response is here. In short: "It appears that substantial [Affordable Care Act] implementation might continue during a lapse in annual appropriations that resulted in a temporary government shutdown for two reasons." The two reasons, in short, are that the government has other pools of money and that Obamacare may be the sort of spending allowed to continue. The letter is much longer and more detailed than this, but the upshot is clear. A shutdown would affect a lot of the sorts of programs that the senators' constituents rely upon. It would almost certainly not, however, stop Obamacare.

Whatever, Ted Cruz will say to these four things. He has a trump card: He won't blink. (See video below.) Therefore your argument is invalid.