Story highlights Polls from the Des Moines Register and NBC News had good news for Republicans

GOP surrogates took to the Sunday shows to cheer their poll results

Democrats say their ground game and campaigns will close the gap

Both parties have their biggest names on the trail Sunday

Republicans woke up Sunday to a wave of new polls that showed their Senate candidates surging ahead in key states -- including one in Iowa that looked particularly grim for Democrats -- giving the GOP a jolt of enthusiasm going into the 2014 campaign cycle's final hours.

Two days from the midterm election, Washington's political class was buzzing around news that Iowa GOP Senate hopeful Joni Ernst was 7 percentage points up in a Des Moines Register poll , and Republican candidates and surrogates popped up on the Sunday news shows, gleeful about their prospects.

"I think the wind is at our back," Kentucky Sen. Rand Paul said on CNN's "State of the Union." He added that Republicans will "in all likelihood" win control of the Senate and added: "I think people are ready for new leadership."

Fueling the Republicans' optimism was a Register poll that showed Ernst leading Democrat Bruce Braley, 51% to 44% -- prompting pollster J. Ann Selzer to tell the newspaper that "this race looks like it's decided."

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Hours before the poll's release, Senate Majority Leader Harry Reid spelled out what a loss in the Hawkeye State would mean for Democrats.

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"Iowa is critical. There's no other way to say it," Reid said Saturday in a conference call with the Progressive Change Campaign Committee.

"Joni Ernst would mean — coming to the United States Senate — that Mitch McConnell would be leader of the United States Senate, who agrees with her on everything," he said, according to Politico

And it wasn't just Iowa that had good news for Republicans. A new set of NBC News/Marist polls unveiled Sunday morning gave Republicans boosts in three key Senate races -- including McConnell's in Kentucky, as well as Georgia, where Democrats had hoped to pickup a seat, and Louisiana, where Democratic Sen. Mary Landrieu is in a tough race for her political career.

Those incumbent Senate Democrats have spent the fall trying to distance themselves from President Barack Obama, whose floundering state-level approval ratings have been a drag for his party down the ticket as Republicans tie their opponents to the commander-in-chief every chance they get.

"This is really the last chance for America to pass judgment on the Obama administration and its policies," former GOP presidential nominee Mitt Romney said on "Fox News Sunday."

Of course, polls are no guarantee for how elections will turn out on Tuesday, as the past several elections for midterms and the presidential race were dogged by major network surveys that turned out to be very different from the actual results. And Democrats cite the 2010 example of Colorado where Republican Ken Buck was consistently polling ahead in the final weeks of that race, only to be defeated by now Sen. Michael Bennet.

Democrats swung back on the Sunday shows as well to make the case that their early voting numbers suggest they'll hold onto some of those seats.

Democratic National Committee Chairwoman Debbie Wasserman Schultz said on ABC's "This Week" that her party's candidates will benefit from get-out-the-vote efforts targeting people who supported Obama in 2008 and 2012, but didn't vote in the 2010 midterm elections.

"We have a ground game that I know [RNC chairman] Reince [Priebus] would take ours over theirs any day of the week," she said.

She also pointed to Democratic surrogates -- including former President Bill Clinton and Secretary of State Hillary Clinton, Obama and Vice President Joe Biden -- and said they trounce GOP surrogates like New Jersey Gov. Chris Christie, Paul and Texas Sen. Ted Cruz.

But Priebus shot back that "our ground game is whipping their ground game."

"Look, if Americans who want change vote on Tuesday, the Democrats are going to have a terrible night. We're going to have a great night," he said. "And it's because Barack Obama's policies and Debbie Wasserman Schultz's policies and Harry Reid's policies are on the ballot."

The GOP needs to pick up six seats to win a Senate majority, and with several other victories all but guaranteed, losses in swing states like Iowa could seal Democrats' fate.

Senate Republican leader McConnell is ahead of Democratic challenger Alison Lundergan Grimes, 50% to 41%, according to an NBC News/Marist survey released Sunday. Democrats had hoped the contest would be among their few chances to pick off a GOP-held seat or at least divert resources from other key Senate races.

Another of those targets is Georgia, but the Republican nominee there, David Perdue, has jumped to a 48% to 44% lead over Democrat Michelle Nunn, the NBC News/Marist survey found.

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That lead might not be enough to clench that race. To win in Georgia, candidates must earn more than 50% of the vote -- and if neither Perdue nor Nunn are able to reach that mark, they'd face each other again in a run-off election in January.

In Louisiana, Democratic Sen. Mary Landrieu is in trouble, too. The NBC News/Marist poll found her at 44% support, but in the state's "jungle primary" she's facing two Republicans -- Rep. Bill Cassidy and tea party candidate Rob Maness. If Landrieu falls short of 50%, she'd face just one of those Republicans in a December run-off -- and without conservatives' votes being split, she'd be the underdog.

The GOP is all but certain to win seats now held by retiring Democrats in Montana, South Dakota and West Virginia. They're also favored in Alaska, Arkansas and Louisiana -- states consistently won by Republican presidential candidates.

Wins in swing state targets like Iowa, Colorado, North Carolina and New Hampshire would offer a huge boost to Republicans' chances -- and would insulate the party from potential losses in Georgia and Kansas, where independent challenger Greg Orman hasn't said who he'd caucus with and therefore can't be considered a reliable supporter of either party.

Top Democrats, trying to narrow the gap, hit the trail Sunday, including Bill Clinton, who planned four stops in Arkansas -- where Democratic Sen. Mark Pryor is endangered and long-time Clinton foil Asa Hutchinson is expected to win the governor's race.

Hillary Clinton, meanwhile, was in New Hampshire, where Sen. Jeanne Shaheen and Gov. Maggie Hassan are both facing stiff challenges in their re-election bids. She'll also attend the funeral for long-time Boston mayor Tom Menino.

Obama, who's stayed away from most Senate races this year with the rare exception of a Saturday visit to Michigan on behalf of Democratic candidate Gary Peters, is in Connecticut Sunday to campaign for Gov. Dannel Malloy.

Republicans are flocking to Kansas, where Orman is threatening to unseat Republican Sen. Pat Roberts. The party's 1996 presidential nominee, Bob Dole, and former Sen. Rick Santorum are campaigning for Roberts on Sunday.

New Jersey Gov. Chris Christie, a likely 2016 White House contender, is swinging through South Carolina, Illinois, Maryland and Pennsylvania. Another potential presidential candidate, Texas Sen. Ted Cruz, is with Republican Dan Sullivan in Alaska, trying to help the Republican knock off first-term Democratic Sen. Mark Begich.

The Florida governor's race -- one of the nation's tightest -- is also getting the attention of big names in both parties. Biden is campaigning for the Democratic candidate, Charlie Crist, while former Florida Gov. Jeb Bush is making stops with Republican Gov. Rick Scott.