Labor Day week ought to start clarifying the partisan battle to control the Senate, but if anything, the picture just got muddier and the map bigger.

An afterthought all year, conservative Kansas is suddenly abuzz.

An independent candidate drove the Democrat from the race and positioned himself to consolidate discontent with three-term Republican Sen. Pat Roberts.

Washington-based GOP strategists are rushing to help Roberts, who's accused of sleepwalking through the race in the deeply Republican state.

If Kansas brought welcome news to Democrats, Alaska did not.

First-term Sen. Mark Begich initially was seen as running a smart campaign with excellent TV ads. But he endured withering criticism for a new type of ad, which he clumsily scrambled to remove from the airwaves.

The ad alluded to a sensational Alaska crime and accused the Republican nominee, Dan Sullivan, of being soft on criminals.

Sullivan was state attorney general at the time, but he had nothing to do with the prison sentence in question.

Critics denounced the ad, the crime victims' relatives demanded its removal, and Begich's image suddenly went from savvy campaigner to truth-shaving attacker.

Democrats acknowledge that it hurt Begich, who's running in a state that President Barack Obama lost by double digits in 2008 and 2012.

"But it hasn't shifted the dynamic that Dan Sullivan is still going to be held accountable for his record," which includes appointments to two state posts and being born outside Alaska, unlike Begich, said Democratic strategist Ty Matsdorf.

For all the noise in Alaska and Kansas, the overall Senate campaign landscape is as tight and unpredictable as before, strategists of both parties say.

"It's within the margin of error almost everywhere," said Republican consultant Mike McKenna, who has conducted recent surveys in several pivotal states.

In terms of gaining new seats, he said, "Republicans can go plus three, or plus 10. It's too close to call."

Nearly all candidates are struggling, McKenna said.

"The Republican brand has been in trouble a long time," he said, thanks to a government shutdown and other steps that raised questions about Republicans' ability to govern.

Yet Obama is damaging the "Democratic brand," McKenna said, by being indecisive on problems such as the racial tension in Ferguson, Missouri, and Islamic extremists' in Syria.

Republicans need six net seats to gain the Senate majority. They are heavily favored to win three where Democratic senators are retiring: West Virginia, South Dakota and Montana.

The most promising targets elsewhere are the four Democrats seeking re-election in states Obama lost, mostly by big margins: Arkansas, Louisiana, Alaska and North Carolina.

The two parties and outside groups are pouring millions of dollars into these states, mostly for TV ads.

The ads' effectiveness is questionable, however, as the North Carolina race between Democratic Sen. Kay Hagan and GOP nominee Thom Tillis illustrates.

No state has seen more political TV ads this cycle, numbering 35,500 so far according to the Center for Responsive Politics.

Many ads rip Hagan for backing the president's health care law. Others criticize Tillis for overseeing a rightward legislative shift as speaker of the state House.

But strategists in both parties say North Carolina voters seem largely uninterested, apparently tuning out the TV ads.

Hagan and Tillis held the first of three televised debates this past week, but it seemed to move the needle little, if any.

In the end, voters may not care so much about Hagan and Tillis, said Paul Shumaker, a top Tillis consultant. "Midterm elections are referendums on the president," he said.

In Kentucky, home to the most expensive Senate race thus far, Senate GOP leader Mitch McConnell almost constantly links his Democratic challenger, Alison Lundergan Grimes, to Obama.

McConnell has never been deeply popular in his state, and strategists say the race remains stubbornly tight despite the many millions of dollars spent on ads, field operations and other campaign tools.

Even some non-Democrats get the "you equal Obama" treatment in GOP-leaning states.

Veteran GOP consultant Chris LaCivita of Virginia, who is being rushed to Kansas to reinvigorate the Roberts campaign, says his team will paint challenger Greg Orman as a "rubber stamp" for Obama.

Orman, once a Democrat and once a Republican, is the independent candidate who rattled the Kansas race by spurring the Democratic nominee's ouster and running ads while Roberts went quiet.

Some top Republicans, however, privately question the utility of continually attacking the president's health law. So they keep stabbing at other issues, too, looking for weak spots.

In Louisiana, the latest charge against three-term Democratic Sen. Mary Landrieu is that she lives in the Washington suburbs rather than in the state.

She says she co-owns a New Orleans home with her parents and siblings. On Friday, a state judge threw out a GOP legal challenge to Landrieu's residency qualifications.

Iowa features another close Senate race, to replace retiring Democrat Tom Harkin. Rep. Bruce Braley, the Democratic nominee, has had some stumbles, and an environmental advocacy group is trying to help. NextGen Climate says it will try to identify and turn out more than 100,000 new Democratic voters in Iowa this fall.

The group has run TV ads hitting Republican nominee Joni Ernst, who has had her own struggles lately. She recently told a group of retirees she doesn't want to privatize Social Security even though she has discussed it "as an option."