MARYVILLE, Mo. – Three weeks after Republican Rep. Todd Akin upended the national political landscape by claiming that pregnancies rarely result from “legitimate rape,” the race for Senate in this increasingly conservative state – and in many ways the battle for control of Congress’s upper chamber – has settled into a waiting game.

A Sept. 25 deadline looms. That’s the last day Akin can petition Missouri courts to remove his name from the ballot – and comply with the near-universal calls from party leaders who think his comments have made unwinnable a seat they need for an easier path to a Senate majority.

Akin’s opponent, Democratic Sen. Claire McCaskill, is waiting, too – hoping that Akin remains in the race but knowing that even if he does, re-election to the Senate is far from secure in a state that has turned sharply against President Obama.

In the balance could lie the Senate. Republicans need four new seats to take control of the chamber. That appeared to be within closer reach for the GOP before Akin’s comment – for which he has apologized – and before Sen. Olympia Snowe, R-Maine, announced her retirement, putting her seat in play.

To win control now, Republicans must see a series of neck-and-neck races turn their way – a surprisingly thin margin of error in a year when nearly two dozen Democratic senators are up for re-election.

“The easiest path to a Republican majority went through Missouri. Without it, it’s steeper and a little more circuitous,” said Jennifer Duffy, an analyst for the nonpartisan Cook Political Report. “It can be done – but they need all the breaks.”

Stuart Rothenberg of the Rothenberg Political Report agreed. The Senate is “still up for grabs,” he said. But he added, “It’s looking harder for Republicans.”

Akin’s rape comments on Aug. 19 breathed new life into McCaskill’s struggling campaign. Now her challenge is to convince Missouri voters that her opponent is too radical not only on women’s issues but across a range of topics.

And so last week, while speaker after speaker at the Democratic National Convention – which McCaskill subtly skipped – alluded to Akin’s stand on abortion, McCaskill embarked on a tour of Missouri college campuses.

“Congressman Akin is extreme and out of the mainstream,” McCaskill told students at Northwest Missouri State University. Akin, she said, “doesn’t understand what his policy positions will do to this state and to the country that we all love.”

But she was not talking about his “legitimate rape” remark, which would have required her to dwell on the touchy issue of abortion. Instead, she was referring to Akin’s contention, in an April debate during the Republican Senate primary, that federally backed student loans represent a “Stage 3 cancer of socialism.”

McCaskill called his position a “head scratcher” in her appearances last week, part of her effort to extend Akin’s controversial remarks to the other corners of their hotly contested Senate race.

“This race will be hard-fought and close,” McCaskill said in an interview. “Anybody who doesn’t think it’s going to be hard-fought and close hasn’t spent much time on the ground in Missouri.”

A St. Louis Post-Dispatch/Mason-Dixon poll taken in the days after the controversy showed McCaskill ahead by 9 points, but other polling has indicated a much tighter race.

The Akin fiasco is only the latest setback for Republican ambitions to take the Senate.

After Snowe announced she would not seek re-election in Maine, former governor Angus King, a popular independent, announced he would run to replace her, probably taking the state out of the Republican column and forcing the GOP to win five seats to guarantee control.

Then came Akin’s interview, on a local St. Louis television station, in which he defended his position of opposing abortion even in cases of rape and incest.

Republicans say they still feel confident about picking up a seat in Nebraska, where polls show Democratic former Senator Bob Kerrey trailing Republican Deb Fischer to replace Democratic Sen. Ben Nelson, who is retiring.

But to win the chamber, Republicans will also have to win a collection of races in which polls have been exceptionally tight. Their opportunities lie in North Dakota, where Democratic former Attorney General Heidi Heitkamp has been running closer than expected with Republican Rep. Rick Berg, as well as in Virginia, Montana, Ohio and Florida.

Even with closer-than-expected contests in Wisconsin and Connecticut, the GOP will need a series of good breaks between now and November – and perhaps a strong pull from the top of the ticket by Mitt Romney – to take the Senate.

Republicans had not figured that one of those breaks would have to come in Missouri.

Immediately after Akin’s remarks, the National Republican Senatorial Committee (NRSC) vowed to spend no money on his race, echoing the disdain of a leading independent super PAC associated with Karl Rove. Rove grew so frustrated with Akin’s refusal to drop out that he jokingly insinuated to wealthy donors at the Republican National Convention about having Akin “murdered.” He, too, apologized.