WASHINGTON — (CNN) House Republicans have had a rough summer.

Donald Trump’s poll numbers slid steadily in key battleground states, their Democratic counterparts outraised them by nearly 3-1 in July, and talk about the Senate GOP majority slipping away triggered fresh worries that the large House majority could also be in jeopardy.

But there is evidence that House Republicans’ strategy to separate their fates from their party’s controversial nominee is working.

Polling data in half a dozen competitive races conducted jointly by House Republican candidates and the National Republican Congressional Committee in recent weeks show that while Trump is trailing Hillary Clinton in geographic regions across the country, House GOP candidates are outperforming their nominee.

The GOP candidates are also leading their Democratic opponents.

Trump’s abysmal poll numbers among Hispanic voters are a factor House Republicans fear could be a drag in several races around the country.

But in Nevada’s third congressional district, a seat Democrats targeted and where Hispanic voters make up roughly 15% of the vote, the GOP candidate, businessman Danny Tarkanian, currently leads Democratic opponent Jacky Rosen by 12 points in a poll that also includes third party candidates.

The same poll, done by the Tarrance Group and the NRCC, has Clinton ahead of Trump in this district by 3 points.

California, a reliably blue state where Democrats are hoping to make some key gains, is an area where House Republicans — at least for now — appear to be holding their own in some districts with sizable Latino voting blocs.

Recent polling by Public Opinion Strategies and the GOP campaign committee shows that in the 7th congressional district in the Sacramento area — one that political handicappers view as an evenly split race — the Republican challenger, Scott Jones, is essentially tied with Democratic Rep. Ami Bera.

The same polls show Clinton leading Trump narrowly there.

Iowa GOP Rep. Rod Blum is one of his party’s most endangered incumbents. Earlier this year, he tweeted out comments in which he essentially rooted for an economic recession in Washington, and Democrats often point to his membership in the conservative House Freedom Caucus as being out of step with his middle of the road district.

Despite Democrats efforts to link Blum to Trump with digital advertising earlier this summer, Blum currently leads Monica Vernon in polling done earlier this month by 7 points according to his campaign’s internal polling.

The same poll shows Trump trailing Clinton in the district by 8 points.

House Speaker Paul Ryan’s home state of Wisconsin is home to another race where the GOP candidate is doing far better in the polls than Trump.

In an open seat in Wisconsin’s eighth district, where GOP Rep. Reid Ribble is retiring, GOP candidate Mike Gallagher holds a 52%-36% lead over the Democratic candidate, Tom Nelson, according to internal polling by Gallagher’s campaign by Public Opinion strategies and the NRCC.

Trump has a much slimmer 3 point lead over Clinton in the district.

House Republican candidates in these races and others are working to put more distance between themselves and Trump, and even walk back earlier expressions of support.

In Jones’ case, he pledged earlier this year he would back Trump, but eased off that in a radio interview in August after the fallout this summer from Trump’s attacks on a Gold Star family.

Speaking with KFBK AM/93.1 FM, Jones said about his vote in November for president, “I don’t know what I am going to do, to be honest with you.”

Democrats have continually pressed for Arizona GOP Rep. Martha McSally to publicly say whether she supports Trump, but she has managed to avoid questions.

Two years ago, McSally won her Tucson-area seat by just 167 votes following a recount.

But recent polling by McSally’s campaign and the NRCC, conducted before this week’s primary to determine whom her Democratic opponent would be, shows her leading either Democratic challenger by nearly 20 points, while Trump is losing to Clinton in the district by 2 points.

Ticket splitting in a presidential year is rare, but some Republicans believe in this odd election cycle voters view Trump in a completely different category than congressional candidates.

“House Democrats’ and the DCCC’s strategy of running a single note, one-size-fits-all campaign is failing, and is just another example of how out of touch they are and why they will continue to flounder in the minority,” Katie Martin, spokeswoman for the NRCC told CNN.

She added: “Voters have seen firsthand that their Republican member of Congress has their back, and they will reward that hard work this fall.”

With a large roughly 60 Republican majority in the House, the math is tough for House Democrats to retake the chamber — they need to pick up 30 seats.

But party strategists downplay GOP polls at this point in the race, arguing they don’t account for “informed voter” input — surveys in which pollsters give more information about the candidates and their stances on issues before assessing match-ups between candidates.

One senior House Democratic strategist familiar with Democratic polling conceded to CNN that while many incumbents and GOP candidates in open seat races are currently leading, they believe GOP support is “soft” and polls will shift in the fall when more voters tune into races below the presidential level.

Rep. Ben Ray Lujan, the chair of the Democratic Congressional Campaign Committee, is holding up the Trump’s candidacy as the reason more people are keeping their eyes on the battle for the House.

In a recent presentation to Democratic donors at a retreat hosted in Napa Valley by House Democratic Leader Nancy Pelosi, Lujan outlined 50 to 60 GOP seats he believes are in play now, according to a senior House Democratic source familiar with the discussion.

He stressed that 10 of these districts — in places like Minnesota, Michigan and wealthy northern New Jersey suburbs — are places Democrats have some traction because of Trump’s negative approval ratings.

In a statement to CNN, Lujan rejected the notion that House Republicans can separate themselves from the top of the ticket, saying, “it’s undeniable that this is a nationalized election dictated by Donald Trump, and House races are shifting based on forces larger than the individual districts themselves.”

The New Mexico Democrat pointed out the seats he views as competitive “just so happens to be where Donald Trump is doing the worst.”

Without predicting the House could turn blue, Lujan said, “House Democrats have great reason for optimism this fall.”

There is still another 68 days until the election, and Republicans concede that Trump’s erratic and unpredictable campaign could still shift the political map.

Democrats pulled in more than $12 million in July, after a successful national convention nominating Clinton, with the GOP raising just $4.6 million.

There is no evidence right now that skittish GOP donors who aren’t funding Trump’s presidential race are actually writing big checks to House Republicans.

And despite the polling, post Labor Day television advertising in many of these races could affect the matchups.

While Democrats raised more money during the summer, both House campaign committees have roughly the same amount of cash on hand heading into the fall.

The NRCC has $64 million, and the DCCC has about $62 million. Outside groups are also starting to ramp up their campaigns on the airwaves.

The biggest question in November will be turnout.

If Clinton’s supporters are more motivated and GOP voters who now say they are prefer Republican House candidates decide to stay home instead of pulling the lever for Trump, the leads the GOP now holds in swing districts across the country could be wiped away.