Democrats are tamping down expectations for a “blue wave” two weeks before the midterm elections as key races in the House tighten and winning back the Senate majority looks increasingly out of reach.

Democratic National Committee (DNC) chairman Tom Perez Thomas Edward PerezClinton’s top five vice presidential picks Government social programs: Triumph of hope over evidence Labor’s 'wasteful spending and mismanagement” at Workers’ Comp MORE said on CNN's “New Day” that he doesn’t use the term “blue wave,” and added that he’s always thought this year’s races would be close.

Separately, Sen. Bernie Sanders Bernie SandersThe Hill's Campaign Report: Trump faces backlash after not committing to peaceful transition of power Bernie Sanders: 'This is an election between Donald Trump and democracy' The Hill's 12:30 Report: Trump stokes fears over November election outcome MORE (I-Vt.), who's campaigning for Democratic candidates, said he doesn’t believe in a blue wave.

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“I know a lot of people talk about this blue wave. I don’t believe it,” Sanders told “Rising” Hill.TV co-host Krystal Ball.

“I happen to think that on election night you’re going to find a very close situation and maybe a handful of votes determining whether Democrats are gaining control of the House,” he said.

The remarks by Perez and Sanders could be seen as a way of motivating the Democratic base.

Many Democrats are convinced that the 2016 presidential race was lost in part because Democratic voters didn’t show up, perhaps because they thought there was little chance that Republican Donald Trump would win.

Talk of a blue wave sends the signal that Democrats have races in the bag, and that voters don’t need to come to the polls on Nov. 6.

“I think it’s really, really smart and if you look at some of our strongest candidates, they’re being very thoughtful and very intelligent on how they’re approaching this, which is always run like your 10 points down,” said Jon Reinish, a Democratic strategist and former aide to Sen. Kirsten Gillibrand Kirsten GillibrandSunday shows preview: Justice Ginsburg dies, sparking partisan battle over vacancy before election Suburban moms are going to decide the 2020 election Jon Stewart urges Congress to help veterans exposed to burn pits MORE (D-N.Y.).

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“It’s less of an expectation management game than it is a turnout game,” he added. “Never say ‘we’ve got this.’ "

At the same time, there are real reasons for Democrats to fret over their chances given President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE’s rising approval ratings, fallout from the fight over Supreme Court Justice Brett Kavanaugh Brett Michael KavanaughTrump faces tricky choice on Supreme Court pick The Hill's 12:30 Report: Trump stokes fears over November election outcome The Hill's Morning Report - Sponsored by Facebook - Trump previews SCOTUS nominee as 'totally brilliant' MORE’s confirmation fight and a strong economy the White House has taken credit for delivering.

Perez still said he has “a lot of confidence” that his party will win back the House.

Democrats have led Republicans on the generic congressional ballot in virtually every public poll conducted over the past year, and an NBC News/Wall Street Journal survey released Monday gave the party a 9-point lead over the GOP in the race to control Congress.

Some Democrats insist that winning the bare minimum of 23 seats needed to flip the House still amounts to a wave.

“Winning 23 seats is a wave,” said a Democratic strategist familiar with House races. “The frustration among some Democrats is losing sight of how big of an accomplishment it is.

“People built expectations for this giant tsunami without the evidence there. The people actually looking at that data, in this fight, know how hard it is and are not taking anything for granted.”

Perez acknowledged, however, that the race for the Senate presents “a tougher map” for Democrats.

More than two dozen of the party’s incumbents are defending their seats this year, including 10 in states won by Trump in 2016, and Republicans are eager to expand their slim 51-49 majority by flipping seats in deep-red states, such as North Dakota, Indiana and Missouri.

Democrats believe they have benefited from an enthusiasm gap with Republicans for most of the year, but there are some signs that GOP voters are getting more motivated ahead of Nov. 6.

Trump has been campaigning across the country and is increasingly using the bully pulpit to steer the national conversation toward issues such as the immigrant caravan headed toward the U.S. border with Mexico — something seemingly designed to fire up his base.

Early voting in some critical battlegrounds as of Monday found that GOP-affiliated voters are outnumbering the Democratic-affiliated voters in Arizona, Florida, Georgia, Indiana, Montana, Tennessee and Texas, according to TargetSmart data analyzed by NBC News.

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Democratic-affiliated voters outpaced GOP ones only in Nevada, according to the report.

Democrats are also worried about laws in crucial pockets of the country that could suppress Democratic voters.

These allegations have become a dominant issue in Georgia’s nationally watched governor’s race between former state House minority leader Stacey Abrams (D) and Republican Secretary of State Brian Kemp. If elected, Abrams would be the first black woman to serve as governor in U.S history.

An APM Reports analysis found an estimated 107,000 voters in Georgia have been removed from the state’s voter rolls because of the “use it or lose it” law, which removes people who have not voted or made contact with an election official over three years.

Kemp, who oversees the state’s elections, said his office is following the law and has worked to prevent voter fraud.

“There are so many ways that Republicans have tried to make voting less accessible to voters over the last two years,” a former DNC aide told The Hill. “We’re really cautious of what the impact of those actions will be going to the polls and how many people are able to vote.”

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Some Democratic strategists are also exercising caution about their midterm prospects because they’re “still a little scarred," in the words of one observer, after Trump’s shock victory over Democratic nominee Hillary Clinton Hillary Diane Rodham ClintonFox News poll: Biden ahead of Trump in Nevada, Pennsylvania and Ohio Trump, Biden court Black business owners in final election sprint The power of incumbency: How Trump is using the Oval Office to win reelection MORE in the 2016 presidential election.

Trump has stepped up campaigning for Republicans in the final stretch of the campaign, attracting thousands of Republicans, while expressing confidence about the party’s prospects.

In recent rallies, the president has also sought to cast Democrats as unfit to govern and has spoken intermittently about a coming “red wave” that would expand the Republican majorities in both chambers.