WASHINGTON (AP) -- In a taste of ads to come, House Democrats have run national TV spots in which actors recount Donald Trump's derogatory remarks about immigrants, women and veterans and one asks, "How can Republican members of Congress support that?"
The commercials, by the Democratic Congressional Campaign Committee, underscore the party's hopes for an Election Day bumper crop of new House seats, fueled by the GOP presidential candidate's disparaging verbal assaults and poor showing in most polls.
Outnumbered by Republicans 247-188 — and with two vacancies in districts they're certain to win — Democrats seem likely to bolster their ranks in November. Yet gaining the 30 seats needed to capture a House majority appears elusive.
Of the House's 435 seats, only around 40 from California to Maine seem clearly up for grabs, though that could change.
Redistricting, along with Democrats' tendency to be concentrated in urban and coastal areas, has given both parties' incumbents such sturdy protection that on Election Day 2014, just 13 of 388 lawmakers seeking re-election lost. Of the 435 House members elected, 377 won by a decisive 10 percentage points or more or were unopposed.
Democrats would have to sweep 35 of the 40 competitive contests and lose only five for a 30-seat pickup, a significant challenge. In the 17 presidential election years since World War II, a party has gained 30 House seats just three times, most recently in 1980.
Democrats' predictions have been tempered. Rep. Ben Ray Lujan, D-N.M., who heads House Democrats' campaign committee, says, "Democrats are on offense and we'll pick up seats."
Democrats failed to recruit strong candidates in districts where they might have competed.
The Democratic challenger against well-financed freshman Rep. Tom MacArthur in central New Jersey, Frederick LaVergne, has reported $600 cash on hand. The party has had problems fielding candidates in the Philadelphia suburbs, eastern Ohio, central Illinois and west of Detroit.
"They haven't put seats in play they needed to put in play," said Rep. Steve Stivers, R-Ohio, a top member of the National Republican Congressional Committee.
Democrats want to pry Republicans out of suburban districts where TV advertising is often expensive, especially with a competitive presidential or Senate race in the state. A week of commercials can cost hundreds of thousands of dollars in Denver; Orlando, Florida; and Las Vegas, and can be prohibitively expensive for House candidates in New York, Los Angeles and Chicago.
In addition, Democrats seem certain to lose a newly redrawn district in north Florida and face challenges keeping seats around Omaha, Nebraska; Sacramento and California's central coast; and Florida's Palm Beach.
GOP DANGER SIGNS
Republicans hold about three in four battleground House seats, leaving them more at risk. Nevada, Maine and Minnesota are places where the GOP faces tough defensive fights.
Thanks to strong off-year elections in 2010 and 2014, the GOP's 247 seats are its high-water mark since Herbert Hoover's presidency 86 years ago. The party holds districts in New York, New Hampshire and Iowa that it will struggle to retain this presidential election year, when Democratic turnout should increase.
While 26 House Republicans were elected in 2014 in districts that backed President Barack Obama in 2012, just five Democrats serve in districts carried by 2012 GOP presidential nominee Mitt Romney.
That means more Republicans are at a disadvantage. Among them, Rep. Robert Dold is clinging to a Chicago-area district that gave Obama 58 percent of its vote, more than in any other Republican-held seat.
Trump is unpopular among women, minorities and college-educated voters. This spells trouble for Republicans representing suburbs and districts with many Hispanic voters, and many candidates have criticized his remarks, though few have abandoned him outright.
Freshman GOP Rep. Carlos Curbelo is fighting to survive in a South Florida district that is two-thirds Hispanic. He's said he won't support Trump and has run a Spanish-language radio ad in which former Florida Gov. Jeb Bush says, "I know Carlos and I know he will continue representing us with integrity in Washington."
Republican Rep. Mike Coffman, whose suburban Denver district is one-fifth Hispanic, says of Trump in one spot, "Honestly, I don't care for him much."
Trump's problems with crucial voters and Democratic nominee Hillary Clinton's modest but distinct advantage in most polls have emboldened Democrats to hunt for additional GOP seats.
They've already spent against conservative Rep. Scott Garrett in New Jersey suburbs of New York City and have hopes of grabbing seats around Minneapolis, Orlando and central New York. They envision benefiting from diminished voter turnout by Republican moderates appalled at Trump and conservatives who distrust him.
"Our biggest concern is turnout," but it's also a problem for Democrats, said Mike Shields, top aide for the Congressional Leadership Fund and the American Action Network, which back House GOP candidates.
Republicans argue that Clinton poses problems, too. Polls find much dislike for her, too, and Republicans are hoping for lower turnout by young liberals who preferred Vermont Sen. Bernie Sanders, Clinton's Democratic presidential rival, and by blacks no longer drawn to vote by Obama.
Should Trump's defeat appear inevitable, House Republicans could cast themselves as a brake on a Clinton administration. So far they've used that sparingly.
One GOP fundraising email signed by House Speaker Paul Ryan, R-Wis., says, "I worry about what will happen if Hillary Clinton is elected president."