In any battle over Senate strategy, the best indicator for the last several years has been Mitch McConnell. The seasoned Capitol Hill veteran and current minority leader hasn't had all that many cards to play during the Obama presidency, but he usually knows how to play them for best effect. McConnell usually wrings as much political advantage as possible, even when outnumbered and outflanked on both sides.

Now, as Congress enjoys its annual extended vacation, McConnell has his work cut out for him. His caucus has split on the strategy for addressing the rollout of ObamaCare.

Pretty much every Republican wants to repeal it, but that's where the unanimity ends. Democrats control the Senate, and voters elected Barack Obama to a second term as president, making repeal impossible. The conservative wing of the GOP in both the House and Senate want to defund ObamaCare, a fight led by freshman Sens. Ted Cruz and Marco Rubio in the upper chamber. Both have turned the budget fight into a test of true conservative credentials, threatening to block any budget with ObamaCare funding included.

Rubio has kicked off a tour in Florida to build support for the defunding effort. Before that, he told conservative radio host Mark Levin that anyone who opposes ObamaCare cannot possibly justify a vote for a budget which funds it. "If you're willing to fund this thing, you can't possibly say you're against it," Rubio argued. "If there was one issue that we should be willing to go to the limit on, this is it."

Over the weekend, Cruz reiterated his demand for defunding the ACA. Speaking at the Family Leadership Summit, Cruz got a standing ovation after declaring, "The only way we win this fight is if the American people rise up and hold our elected officials accountable." Responding to critics of the defunding effort (notably Mitt Romney), Cruz insisted that the time was ripe to stand firm. "In my view, number one, there's bipartisan agreement ObamaCare isn't working. Number two, this is the single best opportunity to defund it."

What is left unsaid here are the presumed presidential aspirations of both Cruz and Rubio, if not in 2016, then in 2020. Cruz won his election in Texas and a national following of grassroots conservatives by promising to hold the line against compromise on principles, chief among them opposition to the Affordable Care Act. Rubio is coming off of the Gang of Eight comprehensive immigration reform bill, which is currently languishing in the House, and which damaged his standing among the same conservative activists. Levin himself called supporters of the Gang of Eight bill "neo-statists," although later offered praise for Rubio in general, apart from immigration. Rubio needs to stay tough on ObamaCare to make up ground with the base after his immigration fight.

Here's where things get tricky for McConnell: Not all conservatives agree with Cruz and Rubio. Washington Post columnist Charles Krauthammer called the defund strategy "nuts," and former Reagan and Bush administrations aide Peter Wehner called it "Marco Rubio's Folly." Both pointed to the fact that Republicans only control one chamber of Congress, not both, and certainly not the White House. Any effort to defund ObamaCare in the Senate will simply fail to pass, and Democrats will pass a budget without Republican votes if necessary, since filibusters cannot be applied to budget issues. If the House doesn't fund the ACA in its budget bills, a conference committee would almost certainly restore funding or stall in the attempt. If Congress doesn't pass a budget over this fight, it won't pit Republicans against Barack Obama, but the Republican House against the Democratic Senate, with Obama able to rise above it all and look more presidential as a result.

Given the current single-digit status of congressional approval, a government shutdown spurred by an ultimatum over ObamaCare is not likely to make Republicans more popular. Instead, it's at least as likely to backfire on them as it did in 1995 when the fight was between a Democratic president and a fully Republican Congress, which Bill Clinton manipulated to his advantage. Conservatives argue that the media tipped the scales at that time, but their media position has hardly improved in the 18 years since that standoff. In a prelude to a midterm election in which the ObamaCare rollout plays to Republicans' strengths, the GOP doesn't need a credibility-damaging budget disaster to derail that momentum before it starts.

National Journal's Jill Lawrence writes that many Republicans on Capitol Hill understand the mathematics of the situation. "Pretty much all the Republicans in Congress oppose the health care law," Lawrence notes. "It's the government-shutdown threat most of them are questioning, because, unlike the outside groups and individuals, they are worried about the real-world impact of such a drastic development — on Americans and on the GOP." Plus, they have to be worried about the inevitable end of a game of chicken this year on an ObamaCare budget fight, with a Senate that can pass Obama's priorities without Republican votes, making a presidential veto threat entirely unnecessary.

This brings us back to McConnell. He signaled this week that he will pursue the alternate strategy of demanding delays in the key mandates of the ACA rather than defunding it. After Obama unilaterally postponed enforcing the statutory deadline for the employer mandate, Republicans have argued that the individual mandate should also be delayed. The Washington Post's Jennifer Rubin reported on McConnell's demand to the CMS administrator for a delay, based on the inability of the selected contractor to ensure data security in the exchanges on time for the ACA's October 1 rollout. "[J]ust last year," McConnell wrote, "it was disclosed that more than 120,000 enrollees in the federal Thrift Savings Plan had their personal information, including Social Security numbers, stolen from your contractor's computers in 2011." McConnell closed with an argument for delay that will be powerful to contradict:

"Americans should not be forced into the exchanges, and certainly not without these assurances. If you rush to go forward without adequate safeguards in place, any theft of personal information from constituents will be the result of your rush to implement a law to meet the agency's political needs and not the operational needs of the people it is supposed to serve."

The delay provides much better fighting ground for Republicans. First, it doesn't hold up the rest of the budget over the latest pitched battle over ObamaCare. After three years of "cliffs," Americans have tired of budget brinksmanship, and even in last year's election didn't do much for Republican electoral efforts when fought over broader issues of budget deficits, tax rates, and national debt. Second, a delay in the exchanges also means a delay in the payment of subsidies, which for the moment will be paid on the honor system, since the delayed employer mandate and a lack of coordination between the IRS and HHS makes it impossible to check income levels for 2014.

Finally, if the Republicans can't win a delay even with the exchanges wide open to fraud and identity theft, they certainly won't be able to win a budget showdown with Democrats over opposition to the whole ObamaCare package. But that may not be the worst outcome, either, especially if the rollout even comes close to the disaster that Republicans predict. Any disaster will help Republicans build support for later efforts to dismantle ObamaCare, and will prove most helpful in 2014. Instead of trying to defend a government shutdown that they can't win, Republicans can instead remind voters that they tried to delay and amend the ACA. That could give Republicans a lot more leverage in the next session of Congress by taking control of both chambers and forcing Obama to defend a train wreck.

That's the smarter course, even if conservative activists want a showdown this year.