Until recently, moderate Republicans had succeeded in flying under the radar during the shutdown crisis. Initially, journalists focused on Speaker John Boehner. Journalists have a penchant to personalize, and Boehner is the most prominent Republican. Some commentators described the current impasse as a result of Boehner’s inadequacies. They offered a Not-So-Great Man theory of history.

Political scientists would be skeptical. In a classic study, Joseph Cooper and David Brady argued that effective leadership style among House speakers is a function of the preferences in their party caucuses. A cohesive party will allow a speaker to exercise a lot of authority. A divided one will reduce the most talented speaker to the role of a broker among factions.

More insightful analyses focused less on Boehner’s alleged failings than on a few dozen “Tea Party” representatives in the House Republican Conference. This is a better reading of the situation than a narrow focus on Boehner, but it still leaves out a lot. Boehner’s adherence to “the Hastert Rule” (bringing forward only bills favored by a majority of the majority party) does not explain how a few dozen Tea Party legislators can determine party policy. In fact, the current crisis is not simply a result of the intransigence of a small number of Republicans on the fringe of their party any more than it is a simple product of Boehner’s leadership style. A much larger group of GOP representatives, not identified as Tea Partiers, are loath to challenge that faction.

Now journalists’ attention is finally turning to House GOP moderates. For several days, more than  two dozen House Republicans have expressed support for a “clean CR,” or continuing resolution without provisions relating to the Affordable Care Act which President Obama and congressional Democrats would accept and which could end the shutdown.

On paper, these moderate Republicans combined with the House Democrats control enough votes to pass such a resolution. Then why doesn’t it happen? Saying Boehner won’t bring up the resolution that moderates claim to support leaves out the fact that these same moderates refuse to sign a “discharge petition” that could bring a continuing resolution to the floor.

Monkey Cage congressional procedure maven Sarah Binder has described the challenges of using the discharge petition procedure in a series of posts. Yet as Josh Barro notes, it’s simply not the case that these Republicans have explored all the procedural options and taken all opportunities to force an end to the shutdown. They have voted against Democratic “motions to recommit” on GOP “mini-bills” that would reopen the government. Effective tactics might involve voting down a rule, or rejecting a ruling of the chair, steps that would be considered quite radical within the partisan context.

And that’s the point, really. Too narrow a focus on rules obscures a more profound political reality; GOP moderates have been unwilling to break from their party on the shutdown issue. In general, Congressional moderates are more closely aligned to their parties than is understood. Often their defections from party ranks occur when it is clear that their party does not need their votes to prevail on a given issue. Moderates frequently represent constituencies in which their parties are not very popular. This gives them a political incentive to create the impression of a certain distance between themselves and their party. Leadership understands this and does not punish legislators for such behavior.

Congressional scholars, including my colleague Frances Lee and Sean Theriault, have shown that legislators are much more likely to stick with their party on “procedural votes” like rules in the House and cloture in the Senate than on up-or-down or “final passage” votes. Procedural votes and discharge petition signatures are harder for voters to understand than final passage votes, but they determine whether a bill ever reaches the final passage stage. For members who want to stay “on the team” the solution is clear: Criticize your party’s extremists, pay lip service to bipartisanship and vote for the eventual compromise when the leadership decides to bring it to the floor. But do not force the leader’s hand or undermine his position.

Why would members engage in this seemingly devious behavior? There are a few reasons. One factor is fear. Even moderates who represent districts in which they see no gain in being identified with the Tea Party brand still fear primary challengers. Recall that Rep. Mike Castle, who had been in office for decades, lost his primary to an opponent who later had to spend the general election denying she was a witch — and not in Utah or in Mississippi, but in Delaware, a state that had voted Democratic in the last five presidential elections. Similarly, the party switch of the late Arlen Specter was based on an understanding that he would lose the impending Republican Senate primary in purple Pennsylvania. Steve Lonergan, the GOP’s current Senate candidate against Cory Booker in deep blue New Jersey, is a Tea Party ally.

In short, GOP primary voters are perfectly capable of nominating Tea Party or other very conservative candidates and unseating more moderate incumbents, even in blue states, and Republican representatives know this. It is unlikely that most of them would lose renomination simply because they broke from their party on the shutdown issue, but it would be a very high-profile defection that would enrage many conservatives, and elected officials are risk-averse.

Secondly, there is substantial pressure within Congress not to break ranks. Some of this is psychological. Members of Congress spend less time mingling across party lines than they used to and “us vs. them” feelings are intense. There is also some price to pay for going against the party leadership. For example, at the end of the last Congress,  some Republicans who had bucked the leadership once too often lost committee assignments.

Finally, we should take far more seriously the under-discussed possibility raised by journalists like Matthew Yglesias and Congress scholars like Robert Van Houweling that some of these legislators are not as moderate as they pretend. Most elected officials were once party activists, a group that is much more polarized than the general public. Moderate Republicans who refuse to sign a discharge petition may not be Tea Partiers in their hearts of hearts, but it is likely that deep down they are more conservative than most of their constituents. Taking visibly moderate stands while quietly siding with their party on “procedural matters” that insure that their moderation will not have any impact allows these legislators to reconcile their personal policy preferences with their electoral concerns. Of course, if these tactics were better understood by the voters and the media that informs them, they would be much less effective.