The annual budget resolution has several purposes. In theory, it’s a mission statement on the proper role of government and a mirror on priorities for the coming decade. At a more practical level, it decides the limit on lawmaker-driven spending for the coming year and smoothes the path toward ambitious changes in federal policy.

And at times when one side controls all of Congress, the fiscal blueprint provides something particularly important: It’s the year’s clearest test of the governing competence of the party in power.

Republicans have asked to be judged by this standard. They won the midterm elections with a pledge to be more effective conductors of the legislative branch if given the keys to the Senate in addition to the House.

If for no other reason, that’s why the electorate ought to keep an eye on the process beginning Wednesday, when the Hill’s two Budget committees open debate on their somewhat different plans for fiscal 2016.

Voters made clear last fall they were tired of a divided Congress and all the excuses for gridlock it incubated. Especially when it comes to writing a budget, none of those rationalizations apply — at least not this year or next. And that’s not only because the GOP now has comfortable majorities on both sides of the Capitol. It’s also because the rules say a budget may not be blocked by a filibuster or quashed by a veto. (That’s because it’s an internal congressional resolution, not a piece of legislation.) The minority party is so totally powerless in the process that in the 114th Congress, the Democrats have effectively been granted an excused absence.

In other words, all it will take for Republicans to show they’ve got a renewed grip on one of Congress’ baseline responsibilities is for 89 percent of their own House members (218 of them) to agree with about 94 percent of their own senators (51).

That may sound relatively easy, given how close to completely unified the party has become in its confrontations with the Democrats. (The CQ Roll Call vote studies for 2014, published this week, offer the most recent supporting evidence.)

But it’s well understood how the biggest threat to the Republicans in this decade has been internal discord. They’ve fractured plenty when dealing exclusively with one another, and their tendency to form circular firing squads looks ready to blossom anew over the budget, the first meaningful test of their stewardship.

The infighting has been especially problematic in the House, where the GOP Restoration was achieved and is still sustained by the tea partiers who view combativeness as central to their mandate. The new Senate GOP majority has the potential to become comparably factionalized — given that it includes a dozen senators elected in the past century, another dozen elected only last year and at least three presidential aspirants.

And on the budget, the two caucuses will need to agree on the same approaches for making several deep GOP fiscal splits go away. Potentially the deepest rift of all is about Pentagon funding.

The budget hawks want to stick with the annual spending caps, one for the military and the other for everybody else, in place for the rest of the decade because of the 2011 deficit reduction law. (The statute also created the across-the-board cuts known as the sequester as the enforcement mechanism.)

The defense hawks are content to keep the strictures on non-defense spending (limiting it to $493 billion next year) but are pushing hard to boost the military budget at least 7 percent above the cap, to $561 billion. (That’s the proposal of President Barack Obama, who also wants to increase domestic spending by a similar amount.)

The Republicans most interested in shrinking the size of government are the bigger bloc of votes, but those more interested in enhancing national security have enough strength in numbers to prevent the other side from winning. The Solomonic solution that’s getting the most early buzz is establishment through the budget of a theoretical “reserve fund” — which would hold the caps in place for now, but allow appropriators to give the Pentagon any savings realized later this year from closing tax loopholes or limiting entitlements.

Plenty of GOP deficit hawks, however, want any savings from simplifying the tax system, shrinking the reach of Medicare or curtailing food stamps to be applied instead toward balancing the federal budget in a decade.

Either way, such changes to the tax code or health care programs would require the special filibuster shield of reconciliation, which only the budget resolution can provide. And blocs of influential Republicans say there are better uses for those unusual powers at the moment. Dismantling the Affordable Health Care Act once and for all is one of them; extracting fiscal concessions from Obama as a condition for increasing the federal debt limit is another.

Of the two new Budget Committee chairmen, Sen. Michael B. Enzi of Wyoming has shown a penchant for pragmatism and deal-making while Rep. Tom Price of Georgia has cultivated a reputation for visionary conservatism. All their combined skills, and plenty of elbow grease from the top GOP leaders as well, will be required to make any budget a reality.

It’s been a decade since Republicans were totally in charge and succeeded in getting the same budget document ratified by the House and Senate. But in 2006, internal strife between the centrists and fiscal hawks sank the GOP budget resolution in the spring, and in the election that fall the party lost both its majorities. After that, Democrats got budget resolutions finished with relative ease the first three years they ran the place. But in 2010 their cohesion so totally unraveled that no budget made it to the floor of either chamber. Their control of Congress was taken away in that year’s election — and the budget process began a period of brokenness that’s the status quo today.

That history makes clear the political consequences for a party that drops the budgetary ball when it’s got a firm grip on Congress.

Related:

For House Budget Negotiators, the Stakes Are High

Lessons for Lovers of Long-Shelved Budget Reconciliation

Ryan’s Rationale for Bypassing 2016

Detailed Budget Policy Coverage from CQ

Lessons for This Year in Voting Patterns of Last Year

2014: Latest Budget Skirmishes: From School Lunch to Immigration

The 114th: CQ Roll Call’s Guide to the New Congress

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