Ted Cruz’s plan doesn’t make much sense on its face. He says he wants to filibuster the House-passed government spending bill that defunds Obamacare. Why would he want to block a bill that accomplishes his dream?

The apparent contradiction underlines the politically difficult position that Cruz has put his caucus in. How do you explain to your constituents that you voted to block a bill that would have defunded the health care law that they so deeply revile? Explaining the arcane rules of the Senate isn’t the easiest political message, though Cruz has earned the backing of big conservative groups to fortify his position.

But the fact that he’s in this position at all probably isn’t a good sign. “Rule No. 1 in communications is if you are explaining, you are losing,” a senior Senate GOP aide told TPM.Some of Cruz’s Senate colleagues have been publicly calling him out on his convoluted tactics.

“I can’t imagine any Republican senator not voting to invoke cloture on a bill they support,” Sen. Bob Corker (R-TN) told Politico.

“I can’t imagine filibustering the bill that I like from the House,” Sen. Lindsey Graham (R-SC) said Monday on Fox News.

Cruz has good reason for opposing “cloture”, the 60-vote threshold that opens and closes debate on bills on the Senate floor. Once the debate is closed, Senate Majority Leader Harry Reid (D-NV) can use a standing Senate rule to strike the defund Obamacare language from the House spending bill with a simple majority vote. Final passage of the bill also requires only 51 votes.

That’s why Cruz has been telling anybody who will listen not to vote for cloture. He wants to paint a vote for cloture as a vote for Obamacare, even if it’s technically the opposite. It’s his new message, seemingly designed to combat the pushback from skeptical members like Corker and Graham while giving his plan political cover.

“I’ll tell you, any vote for cloture, any vote to allow Harry Reid to add funding for Obamacare with just a 51-vote threshold, is a vote for Obamacare,” Cruz said Sunday.

But parliamentarian tactics aren’t the easiest thing to convey to the public at large. That’s why the endorsement of major conservative groups like Heritage Action and the Senate Conservatives Fund could be a big boon for Cruz. Both groups have backed Cruz’s approach, and Heritage said it would be scoring how senators vote on cloture.

Senate Conservatives Fund president Matt Hoskins repeated Cruz’s line in his own statement: “It’s pretty simple — any Republican who votes for cloture is voting to fund Obamacare.”

But the other two big conservative organizations — Club For Growth and FreedomWorks — haven’t yet taken a position on the Cruz plan. They declined to respond to TPM’s requests for comment Monday. Their public silence leaves the signal from the grassroots unclear for now, as members weigh a politically muddied vote.

And a statement from FreedomWorks president Matt Kibbe last week after the House vote (but before Cruz announced his plan) again underscores how complicated the GOP’s messaging over the next week is going to be.

“We will consider scoring any votes in either chamber of Congress involving the Continuing Resolution as key votes on our online Congressional scorecard,” Kibbe said, “in favor if the bill continues in its present form, but against any modifications that allow further funding for the Washington health care takeover.”

By the letter of that statement then, Cruz is running afoul of FreedomWorks because he wants to block the House bill in its current from. But he’s fulfilling its spirit because, in the end, Cruz is trying to stop the defund provision from being eliminated.

Other Senate Republicans seem to be trying to thread this rhetorical needle in their own cautiously worded statements. Here’s what Senate Minority Whip John Cornyn (R-TX) tweeted Monday:

I intend to support the House bill that defunds Obamacare and will vote against a bill that funds it. — JohnCornyn (@JohnCornyn) September 23, 2013

If you dig into that sentence, you see the difficulty of the Senate GOP’s position.

Cornyn says he supports the House bill, which Cruz says he will block. So Cornyn could actually vote for cloture — against the wishes of Cruz, Heritage, etc. — because he supports the House bill and wants it to come to the floor. That would be in line with the tweet above.

But then when Reid strips the defund language from the bill, he could vote against its final passage. With both votes, Cornyn is voting for defunding Obamacare, yet defying Cruz. FreedomWorks might score for him; Heritage would score against him.

Confused yet? That’s the position that the Senate GOP finds itself in.