The GOP is sure to try to convince Ryan (left), Perry and/or Christie to run. | AP Photos With Daniels out, GOP hopes for new options

Mitch Daniels’s overnight decision against a presidential bid will immediately raise the volume on the low-hum grumbling among Republican insiders that they’re gearing up to face President Obama with the weakest primary field in recent memory.

Advertisement The pressure on a handful of Republicans who’ve insisted they won’t consider running but would be potentially strong alternatives to Mitt Romney will now significantly intensify, but the ultimate beneficiaries of Daniels’s absence may be two candidates already on course to run: Tim Pawlenty and Jon Huntsman. At the moment, though, the Indiana governor’s exit illustrates the degree to which the GOP race is being shaped by who’s not running. Consider the list of would-be candidates who’ve passed on a campaign in the last four months: Mike Pence, John Thune, Haley Barbour, Mike Huckabee, Donald Trump and now Daniels. Add Jeb Bush, Chris Christie, Paul Ryan and Rick Perry – Republicans with star power who’ve said flatly they won’t run – and it translates into a GOP establishment deeply worried that the flawed options they’re left with won’t be any match for an incumbent president who seemingly won’t face a primary but is likely to shatter campaign fundraising records. “Insofar as politics abhors even a near-vacuum, others are bound to get in,” Weekly Standard editor William Kristol predicted this morning, suggesting a race that could “remain open and fluid until Thanksgiving.” One Daniels friend and longtime Republican, who had already gotten dozens of emails by 7:30 bemoaning the news, was blunt when asked about who in the current field was now more appealing: “None of the above.” In the near-term, Daniels’s exit means that Republican donors, operatives and elected officials aren’t likely to keep taking no for an answer and will surely attempt to convince one of the would-be candidates who’ve already rebuffed entreaties to reconsider. Given the ties many of these GOP professionals have to the Bush family, that means there will almost certainly be another effort at Jeb Bush, the former two-term governor of Florida. But, given his public and private comments about not running in 2012, that campaign is likely to fall short. In an emailed statement, Bush reiterated his decision to stay out. "While I am flattered by everyone's encouragement, my decision has not changed," Bush wrote. "I will not be a candidate for president in 2012." The more prime target may ultimately be Christie. The pugnacious New Jersey governor, in just his second full year in office, has jokingly threatened to commit suicide to convince people that he’s not going to seek his party’s nomination – but has also continued to show an appetite for staying in the national conversation. He’s a fixture on national TV, has hosted a succession of potential candidates to ring-kissing session at the governor’s mansion and will receive a group of Iowa Republicans there later this month who want to draft him into the race. For Christie, who has only middling poll numbers and faces a potentially difficult reelection in 2013, now could be his best opportunity to seek the presidency.

Christie’s top political adviser, however, reiterated Sunday morning that the governor wouldn’t get in.

“The makeup of the field has never been part of his thought process,” said Mike DuHaime. Asked if Christie was still 100 percent not running, DuHaime said: “Correct.”

For his part, Ryan said Sunday that he also wasn’t going to launch a bid - but didn’t completely slam and bolt the presidential door shut.

” I’m not running for president, I’m not planning on running for president,” Ryan said on NBC’s “Meet the Press.” “If you’re running for president you gotta do a lot of things to line up a candidacy and I’ve not done any of those things. It’s not my plan. My plan is to be a good chairman of the House Budget Committee and fight for the fiscal sanity of this nation”

Yet when pressed Ryan, who talked to Daniels on the phone Saturday night about the governor’s plans, added: “You never know what opportunities present themselves way down the road. I’m not talking about right now. And I want to focus on fixing the fiscal problems of this country.”

A spokesman for Perry, too, left just a bit of wiggle room Sunday.

“The governor’s position hasn’t changed,” said Perry aide Mark Miner. “He has no intention to run for president and is focused on the current legislative session.”

If recent political history is any guide, some establishment-friendly candidate will emerge to fill the void. When Democrats yearned for more options in 2003 and Republicans did the same four years later, Wesley Clark and Fred Thompson, respectively, heard the call and got in after Labor Day.

But their failed candidacies are instructive: It’s rare that a late-entrant can get into the race, build an organization and within a few short months be competitive in the first caucuses and primaries.

So, for now, the Republicans are left with what many see as, “the weakest Republican field since Wendell Willkie won the nomination on the sixth ballot in 1940,” as GOP strategist John Weaver recently told TIME.

But should Huntsman, Weaver’s own would-be candidate, decide to get in the race next month, there could be a real battle for the nomination.

That would mean Romney would face a serious test in Iowa against Pawlenty, who is set to announce his candidacy there tomorrow, and in New Hampshire vs. both Pawlenty and Huntsman, the latter of which is in the midst right now of an extended trek through the Granite State.

And beyond the three-way between the establishment types, there will almost certainly be a conservative populist candidate who emerges to take some of the support Huckabee and Trump enjoyed in early polling. That could mean Sarah Palin, should she come off the sidelines, but it could just as easily be a figure like Michele Bachmann, who, unlike Palin, is already edging into the race.

Without Daniels, however, it’s the mainstream Republicans not named Mitt Romney who stand to benefit.

In short, the space to be the Romney alternative just got a lot bigger.

That helps Pawlenty significantly, who has been working diligently at putting together a campaign infrastructure for over two years but is still little known among rank-and-file voters. He can now say to both donors and activists much more convincingly that, no, the political version of the knight in shining armor is not going to suddenly emerge to dispatch Romney. Those Republicans that had cast their lonely eyes to Indianapolis can now fix their gaze back on candidates like Pawlenty already putting in long hours on the trail from Sioux City to Concord.

The former Minnesota governor’s argument is simple: He can appeal to the full spectrum of the Republican Party’s social conservatives, tea party activists and regular committee types in a way that Romney and Huntsman, because of their past apostasies, cannot.

So Pawlenty will get a second and much longer look from the hyper-engaged Republican crowd and face significantly less competition for attention among the many voters who’ve yet to tune in.

Huntsman, too, could get a boost. His initial foray into New Hampshire this weekend, a state which will be pivotal to his prospects, garnered positive reviews and he’ll benefit from not having Daniels claim some of the anti-Mitt crowd there. Further, from a message stand-point the Hoosier and Huntsman were likely going to occupy some of the same space. Both have been decrying the tone of modern politics and were appealing to Republicans less driven by a social agenda than by a hunger for a pragmatic, results-oriented candidate. The two have also, along with Barbour, taken a much more skeptical view of American intervention abroad than the more hawkish Romney and Pawlenty. And, given his personal wealth, should Huntsman reverse course and decide to self-fund he could emerge as the only candidate in a post-Daniels field capable of keeping reasonably close to Romney on the fundraising front.

Nobody, however, is likely to raise the sort of money Romney will over the next six months at which point the primary begins. He raised over $10 milion in a single day last week and some of his fundraisers expect him to post at least $40 million for the quarter.

So even as the two chief Romney alternatives wake up Sunday morning and exalt about the cleaner shot they now have at the frontrunner, the oft-derided former Massachusetts governor also now faces a clearer path to the nomination.

Without Daniels in the race, Romney at the moment faces no Republican who can put together as robust a fundraising network.

That means Romney’s “long slog” approach to the nomination is now much more realistic: without significant cash, who else can go the distance?

He has tred carefully in Iowa so far, but there’s now one less Midwestern governor competing there. Should Pawlenty and a handful of other, more conservative candidates divide up the vote there that Huckabee won in 2008, Romney could win in a plurality, then capture New Hampshire and effectively wrap up the nomination. But even if a Pawlenty or a right-wing Republican takes the caucuses, that doesn’t necessarily mean they’d be formidable for the long haul delegate battle.