With one week to go, Republicans' confidence builds

The final week in a two-year war for control of the Senate is going down to the wire, with Republicans confident they’ll net at least the six seats they need to gain a majority during President Obama’s final two years in office.

Republicans are all but assured of winning the open seats vacated by retiring Democrats in Montana, South Dakota and West Virginia and have a very good chance of ousting Democratic incumbents in Alaska, Arkansas, Colorado and Louisiana.

The GOP also believes it will win an open seat in Iowa, where Republican state Sen. Joni Ernst is in a dogfight with Rep. Bruce Braley (D).

Democratic incumbent Sens. Kay HaganKay HaganPhoto finish predicted for Trump, Clinton in North Carolina Are Senate Republicans facing an election wipeout? Clinton's lead in NC elevates Senate race MORE and Jeanne Shaheen are polling better in North Carolina and New Hampshire, respectively, but those races aren’t sure things for the party either.

Nothing is certain in an unpredictable election year in which incumbents in both parties have come under fire.

Sen. Pat Roberts (R-Kan.) faces a tough independent challenger in Greg Orman, and Democrat Michelle Nunn has made a run on Republican David Perdue in Georgia, putting a once safe Republican Senate seat at risk.

“We’re seeing an unusually large number of very, very close races,” said Jennifer Duffy, senior editor at The Cook Political Report, a prominent handicapper.

Still, the $4 billion midterm campaign is ending with Republicans feeling bullish that Sen. Mitch McConnellMitch McConnellRubio: GOP Congress could go in different direction than Trump Pelosi blasts GOP leaders for silence on Trump Reid: Groping accusations show Trump’s ‘sickness’ MORE (R-Ky.) will unseat Sen. Harry ReidHarry ReidPelosi blasts GOP leaders for silence on Trump Latinos build a wall between Trump and White House in new ad The true (and incredible) story of Hill staffers on the industry payroll MORE (D-Nev.) as majority leader.

“The pundit class on both sides of the aisle has focused too much on individual races that might be aberrant. The overall data is overwhelmingly positive for Republicans,” said Vin Weber, a Republican strategist who served as a senior advisor to several Republican presidential candidates.

Weber says it will be very difficult for endangered Sens. Mark BegichMark BegichTrump campaign left out of Alaska voter guide Ryan's victory trumps justice reform opponents There is great responsibility being in the minority MORE (D-Alaska), Mark Udall (D-Colo.), Mark PryorMark PryorCotton pitches anti-Democrat message to SC delegation Ex-Sen. Kay Hagan joins lobby firm Top Democrats are no advocates for DC statehood MORE (D-Ark.) and Mary LandrieuMary LandrieuTrump’s implosion could cost GOP in Louisiana Senate race Louisiana needs Caroline Fayard as its new senator La. Senate contender books seven-figure ad buy MORE (D-La.) to overcome polling deficits, even if they are trailing by only a few points because of the macro political environment.

“If you are an incumbent Democrat, you are at 45 percent or lower, you’re behind your Republican challenger and the president’s approval rating is under 40 percent in your state. Is that really a close race?” he said.

The two parties are fighting over polls, with Republicans noting that its candidate in South Dakota is pulling ahead, and Democrats showcasing a poll by Harstad Strategic Research showing Sen. Mark Udall (D-Colo.) up by a point, 44 to 43 percent.

Democratic strategists argue their superior get-out-the-vote operation will cut two or three points from any survey advantage enjoyed by a GOP candidate.

Democrats are also putting their faith into early-voting efforts, something the party believes could save Braley in Iowa.

“Democrats have a lead in raw amount of ballots that have been returned but when you add in the independents, which we are confident are almost 2-to-1 in our favor, we have an even bigger leader,” said Justin Barasky, a spokesman for the Senate Democrats' campaign arm.

Sean Spicer, the spokesman for the Republican National Committee, counters that while Democrats may have cast more early votes in the Hawkeye State, they are not matching their performance from past years.

He said Democrats had a 22,000-vote advantage after early voting in 2010 but still lost the gubernatorial and Senate races.

In addition, the Republican get-out-the vote operation is substantially improved compared with past years.

“We have the best ground game this party has ever put out there in midterm elections,” he said.

Republicans are poised for big House gains on election night as well, but could still fall short of their ambitious goal of netting 11 seats for an historic 245-seat majority. GOP strategists are cautiously optimistic their net wins will be in the high single digits, while Democrats privately admit their losses could climb well past that.

Hobbled by President Obama’s sagging approval ratings, Democrats are almost exclusively playing defense a week out. Early offensive targets are now a distant memory, and they’ve even had to put late money into protecting incumbents and open seats in Hawaii, Iowa and Nevada they never expected to be competitive.

The open seats from retiring Reps. Mike McInytre (D-N.C.), Jim Matheson (R-Utah) and Bill Owens (D-N.Y.) are sure goners for Democrats.

Republicans concede they’ll lose the seat of retiring Rep. Gary Miller (R-Calif.), and self-inflicted wounds have also endangered the fates of Reps. Steve Southerland (R-Fla.) and Lee Terry (R-Neb.).

But apart from there, GOP pickups are ripe for the taking. Blue Dog Reps. Nick Rahall (D-W.Va.), John Barrow (R-Ga.) and Collin Peterson (D-Minn.) face their toughest races ever, and in West Virginia especially the president’s staggering approval ratings could be Rahall’s undoing.

Even New York Democratic incumbents once thought safe, such as Reps. Sean Patrick Maloney and Dan Maffei, find themselves in nail-biters, and perpetual target Rep. Tim Bishop is in a race too close to call. Democrats even concede that embattled Rep. Michael Grimm (R-N.Y.), facing a 20-count federal indictment and looming trial, could defy the odds and somehow win.

On the state level, party strategists are most concerned about the races in Wisconsin and Florida because of their potential impact on the 2016 presidential race.

Wisconsin Gov. Scott Walker (R), a likely top-tier White House hopeful in 2016, is in a dead heat with former state Secretary of Commerce Mary Burke (D). A loss would hurt his viability for the presidency.

“The most interesting governor’s race is in Wisconsin. No one loves Scott Walker but I don’t know if Mary Burke can seal the deal,” said a senior Senate Democratic aide.

In Florida, control of the state government could give one party or another an advantage in an important battleground state that decided the 2000 presidential election.

— Jessica Taylor contributed.