Senate Minority Leader Mitch McConnell did not want to have to vote to advance the debt ceiling bill, not with a primary looming and not with the issue being unpopular with conservatives. But his caucus, it seems, didn't give him any choice.

On Wednesday afternoon, Texas Sen. Ted Cruz threw the latest of his never-ending supply of wrenches into what was expected to be a fairly rote approval of a debt ceiling increase that had already emerged from House Republicans. Cruz's filibuster of the bill meant that some Republicans on the Senate side would have to join the Democratic majority in voting for cloture, allowing the expected party-line approval of the measure to move on to the president. As The Wire reported, few Republican senators were particularly eager to be the ones to take that vote. After all, the party had spent two-and-a-half years intentionally conflating the debt limit with the idea of increased debt spending and insisting that it could force concessions from President Obama any time the limit needed to be lifted. Last October proved that the strategy wouldn't work, but the messaging has not yet caught up to the reality.

The other problem, the bigger problem, is that McConnell and other Republicans are facing conservative primary challenges over the next few months that make having to vote in opposition to a benchmark conservative issue particularly inconvenient. The upstart Senate Conservatives Fund, a group founded by former Sen. Jim DeMint, has been effective at drawing attention to these conservative challengers, like Matt Bevin in Kentucky, who's trailing McConnell by a decent margin. But even as Wednesday's debate played out, the SCF was pushing the anti-McConnell ad you can see at right. "Mitch McConnell is trying to bully and intimidate conservatives just like the IRS is," the voiceover states.

At that moment, according to Politico, it was McConnell who was getting bullied. Prior to the cloture vote, only Illinois Republican Sen. Mark Kirk had committed to voting to end the filibuster. Other members of the party balked, wanting to make their leadership … well, lead.

Miffed that they have long been asked to take tough votes when the GOP leaders voted ‘no,’ Sens. Susan Collins of Maine and Lisa Murkowski, privately pressured McConnell and [Senate Minority Whip John] Cornyn to vote to break the filibuster, sources said. Murkowski resisted voting for the measure without the support of her leadership team.

It was a breaking point for what The New York Times' Carl Hulse calls the "Vote No, Hope Yes" strategy. Republicans knew the debt ceiling bill needed to pass, but none of them wanted to be the ones to pass it for political reasons. "Most Republicans badly wanted the debt limit to be raised — particularly since the House had already left town and Wall Street was unlikely to look kindly on a potential default," Hulse writes. "They just did not want their fingerprints on it." Cruz — who, we'll note, used to be pretty close with the Senate Conservatives Fund — left them no choice.

"McConnell just gave Obama a blank check," RedState's Erick Erickson wrote this morning, echoing the "debt ceiling increase equals increasing spending" falsehood that's gotten Republicans into the schizophrenic position they now hold. How to respond to McConnell in Erickson's opinion? Give money to the Senate Conservatives Fund. "If I could give the Senate Conservatives Fund a blank check, I’d do so."

Neither McConnell nor Cornyn — who's running against the deeply quixotic Rep. Steve Stockman — is likely to lose his primary. But McConnell doesn't even want to worry about it. This is the guy who last April was preparing to launch a full assault against an Ashley Judd candidacy that wasn't even confirmed to exist. McConnell doesn't want to have to put his position at risk. That's the thing about being a Senate Minority Leader, though. Sometimes, you have to lead.