West Virginia Gov. Joe Manchin (D) was supposed to have an easy road to the Senate once Rep. Shelley Moore Capito (R) decided against challenging him in November's special election.

But the latest Rasmussen poll on the race shows Republican businessman John Raese within six points of the popular governor.

Manchin is running in a special election to fill out the remainder of the late Sen. Robert Byrd's (D) term.

The new poll gives Manchin 48 percent of the vote to Raese's 42. Another 4 percent prefer another candidate, and 7 percent remain undecided. The survey polled 500 likely voters and has a margin of error of plus-or-minus 4.5 percentage points.

An earlier Rasmussen poll on the special election had Manchin up 51-35.

Even though he holds just a six-point edge, Manchin's overall approval is high. The poll found that 70 percent of likely voters approve of the job Manchin is doing as governor.

So what's dragging Manchin down? Rasmussen suggests it's President Obama's unpopularity in the state, which Manchin's Republican opponent has made the hallmark of his campaign. Raese, who is expected to pour plenty of his own money into the campaign, has already run TV ads hitting the president.

Among the 34 percent of voters who just "somewhat approve" of the job Manchin is doing as governor, 64 percent strongly disapprove of the president's performance. Raese also holds a 45-40 edge among unaffiliated voters in the state.

The Raese campaign quickly trumpeted the results of the poll in an e-mail blast, while Manchin's camp dismissed Rasmussen as a "Republican pollster."

Republicans have taken a 10-point lead on the generic ballot question in Gallup's latest tracking poll — the largest lead either party has ever held ahead of a midterm election since Gallup began asking the question in 1942.

The GOP leads 51 percent to 41 among registered voters, and Republicans are up four points from last week's tracking numbers.

Gallup notes that prior to 2010, the largest advantage for Republicans on the generic ballot question came in the summer of 2002 and 1994, when the party held a five-point edge. Republicans gained seats in both of those years, taking back control of Congress for the first time in decades in '94.

"The last Gallup weekly generic ballot average before Labor Day underscores the fast-evolving conventional wisdom that the GOP is poised to make significant gains in this fall's midterm congressional elections," writes Gallup's Frank Newport, who said the numbers suggest 2010 could be a major wave election for the GOP.

"Republicans' presumed turnout advantage, combined with their current 10-point registered-voter lead, suggests the potential for a major 'wave' election in which the Republicans gain a large number of seats from the Democrats and in the process take back control of the House," writes Newport.

One caveat Gallup does include in its analysis is that Democrats were actually ahead on the generic ballot question earlier this summer, so there is enough volatility in the electorate for things to shift ahead of November.

But as Nate Silver notes, the deficit is significant, and could be even larger than it seems. Gallup is still polling registered voters, as opposed to likely voters. The pollster will shift to likely voters closer to the fall.

Silver writes: "At FiveThirtyEight, we’ve found that the gap between registered and likely voter polls this year is about 4 points in the Republicans’ favor — so a 10-point lead in a registered voter poll is the equivalent of about 14 points on a likely-voter basis."

— Updated at 9:10 a.m.

The Democratic Congressional Campaign Committee (DCCC) is up with its first ad of the 2010 cycle, and its target is Republican congressional hopeful Sean Duffy. 

Duffy is up against Wisconsin state Sen. Julie Lassa (D) in the race for retiring Rep. David Obey's (D-Wis.) seat. The race is considered a toss-up this November. 

In the 30-second spot, the committee hits the Sarah Palin-backed Republican on social security, accusing Duffy of backing a plan to privatize the benefit. "When we should be fighting to protect social security, Sean Duffy backed a plan to privatize it," the ad claims.  

The National Republican Congressional Committee fired back, calling the ad "deliberately misleading." The DCCC ad is the opening salvo in a district that will likely see plenty of outside spending this fall. Lassa has the backing of the women's advocacy group EMILY's List, and both party committees have the district in their crosshairs.  

In a letter to Florida Gov. Charlie Crist (I) dated Monday, the National Republican Senatorial Committee asked the candidate for Senate to return the money it donated to his campaign when he was still running as a Republican.

The NRSC gave $10,000 to Crist's campaign last summer.  

The committee's executive director, Rob Jesmer, mocked Crist in the letter, writing, "I am so pleased to learn about your latest flip flop yesterday regarding the return of contributions upon request. After months of refusing to return donations from hardworking voters and others who supported your candidacy while you were a Republican, you told CNN’s Ed Henry yesterday, 'We'll give it [campaign contributions] back to people who had asked for it.' " 

Jesmer goes on to tie Crist to indicted former Florida GOP Chairman Jim Greer. Earlier this month, Crist returned the $10,000 Greer donated to his Senate campaign after the former party chairman asked for the money back. 

Jesmer notes that his letter marks the committee's second request for their funds back.

"I’m writing you today to let you know that we will gladly take you up on your latest offer — please consider this letter yet a second official request that you return all contributions from the NRSC and from the Republican Senate leadership," Jesmer continued. "After you switched your position on health care, the stimulus, off-shore drilling, and a number of other critical issues facing the state of Florida, this may actually be one flip flop that that we can support."

The Crist campaign also received $40,000 from the PACs of other Republican senators, including $10,000 each from the committees of Sens. John Cornyn (R-Texas), Lamar Alexander (R-Tenn.) and Minority Leader Mitch McConnell (R-Ky.). 

-Updated at 5:17 p.m.

AFL-CIO officials will be barnstorming the country on behalf of Democratic candidates during the Labor Day weekend.

President Richard Trumka will appear Sunday with Gov. Ted Strickland (D) in Ohio.

Secretary-Treasurer Liz Shuler will campaign Monday with Jerry Brown, the Democratic candidate for governor of California, while Executive Vice President Arlene Holt Baker will campaign over the weekend in Florida, a state featuring a series of key congressional races plus a Senate race and gubernatorial race this fall.

Two of the states are important this year because of the governor's role in the redistricting process — Ohio is predicted to lose two House seats after the 2010 census is complete, while Florida is expected to gain one. California is predicted to remain the same but the state has some of the largest union memberships in the country. 

All three states will be important in the 2012 presidential race.

On Labor Day, Trumka will be in Milwaukee for a rally with President Obama and Secretary of Labor Hilda Solis.

The Tea Party Express, which spent some $600,000 on Alaska Republican Joe Miller's primary challenge to Sen. Lisa Murkowski (R), says it's preparing to do the same on behalf of Christine O'Donnell (R) in Delaware.

O'Donnell is challenging Rep. Mike Castle (R-Del.) from the right in the state's Sept. 14 Senate primary, but she has yet to capture the same kind of attention from conservative activists as other Tea Party-backed candidates have this cycle. 

Tea Party Express spokesman Levi Russell said Monday that his organization is already cutting TV and radio ads in Delaware and expects to be on the air by the end of the week. Russell said he hopes to match the support the group offered in GOP primaries in Utah, Nevada and Alaska this year.  

"All of our spending is dependent on the enthusiasm of the Tea Party Express members," Russell said. "It's up to that race and that candidate to capture their imagination."

As to whether O'Donnell has done that to this point, Russell admits "not quite yet." But he expressed confidence that the money will flood in over the coming days.   

"I'm sure we'll be spending six figures in Delaware," Russell predicted. Read more...

Alaska's Libertarian Party over the weekend closed the door on a potential run by Sen. Lisa Murkowski on its ballot line this November. 

Murkowski is still battling Tea Party-backed Joe Miller, who leads her by less than 2,000 votes in the state's Republican primary. Some 24,000 ballots must still be counted. But speculation about a third-party or independent run for Murkowski in November began almost immediately after last Tuesday's primary. 

The vice chairman of the state's Libertarian Party, Harley Brown, told The Hill that a supporter not affiliated with the Murkowski campaign reached out to the party and inquired about the possibility of a Libertarian run for Murkowski, should she end up losing to Miller in the primary.

"We started getting all sorts of calls and people were starting to speculate, so we just decided to put an end to it right away," said Brown. "We unanimously decided that it wouldn't happen." 

The vote was 5-0, according to Brown. 

The midterm election forecast is growing more dire for Democrats as the summer wears on, and that's reflected in The Ballot Box's race ratings for the 2010 elections.

The latest update shows growth in the ranks of the toss-up category on both the House and Senate side.  

Democratic incumbents continue to struggle and general election polling across the country has Republicans running strong against several Senate incumbents. In all, eight Democratic-held Senate seats are now considered toss-ups, while the ranks of Democratic-held House seats in the toss-up category swells to 29.  

One bit of good news for the ruling party in these new rankings — at least one Democratic-held seat has become less competitive ahead of November, shifting from our "toss-up" category to "lean Democratic."

Check out the chart; some of the updates are after the jump:

Attorney Joe Miller said "we are watching the process closely; when we see inappropriate actions taken, we file a complaint."