WASHINGTON—In one Democratic ad, a grunting, helmet-wearing actor portraying GOP Rep. Jon Runyan of New Jersey, a former football lineman, physically blocks seniors from their Medicare benefits.

Another TV ad accuses Massachusetts House GOP hopeful Richard Tisei, an openly gay state senator, of being "too extreme" and links him to the tea party as it flashes pictures of Sarah Palin, Rush Limbaugh and Newt Gingrich.

A Republican spot pounds Rep. Mike McIntyre, D-N.C., for his state's high unemployment, showing a barren factory floor and blaming him for backing President Barack Obama's "wasteful" economic stimulus bill.

Democratic House challenger Christie Vilsack of Iowa is accused in an ad of backing Medicare cuts and Obama's health care overhaul. "She's fighting for Obama, not you," the narrator says.

With the Nov. 6 election fast approaching, Democrats and Republicans dueling for House control are focusing on poll-tested themes in their attacks. Yet even as Republicans gauge what impact presidential nominee Mitt Romney's recent struggles might have on House races, the outlook seems essentially unchanged. Democrats may gain a few seats and perhaps do a bit better than was expected weeks ago, but they seem unlikely to grab the additional 25 seats needed to take over the chamber.

Of the 435 House districts, only about 60 are considered competitive and roughly 30 others seem potentially in play, evidence of the limited targets both parties have for pickups. Unlike the national voting trends that produced large House gains by Democrats in 2006 and 2008 and then by Republicans in 2010, analysts don't see either side's candidates enjoying a decisive political wind this time.

"The electorate appears to be weary, weary of promises and weary of any new, bold policy directions," said Charles Stewart III, a political science professor at the Massachusetts Institute of Technology who has studied Congress. "There's no groundswell of public support" for either side.

Republicans controlled a peak of 242 House seats in this Congress, their high-water mark since just after World War II.

Several longtime lawmakers are in tight races, including 26-year veteran Louise Slaughter, D-N.Y., and Roscoe Bartlett, R-Md., serving in his 20th year. But two dozen of the toughest contests involve members of the House GOP freshman class of 2010, when tea party fervor helped sweep 87 of them into office.

Though freshmen are perennially among the most vulnerable, the last election's conservative crop helped drive House leaders into headline-grabbing showdowns with Obama over federal spending and borrowing. Democrats are trying to cast them and House Republicans overall as obstructionists with extreme views.

Some freshmen show little sign of backing down. "I'm a constitutional conservative standing up for the principles and values of this country," said Rep. Allen West, R-Fla., one of the House GOP's leading money raisers.

Others are projecting softer messages.

While Rep. Frank Guinta, R-N.H., called himself "a tested conservative" and spoke of being "fed up with Washington" in 2010, his 2012 ads have focused on the rising federal debt and say, "My No. 1 priority is helping people find jobs."

One GOP advantage this year is money, lots of it.

Republican House candidates have raised $373 million since this campaign cycle began in 2011, and that's about $100 million more than Democrats, according to the nonpartisan Center for Responsive Politics. The National Republican Congressional Committee, the House GOP's campaign arm, has spent about $20 million since last year in independent expenditures for or against candidates, well above the Democratic Congressional Campaign Committee's $14 million, the center says.

More money is certain to come from outside groups that can legally spend unlimited funds to help candidates.

American Crossroads and Crossroads GPS, affiliated with GOP strategist Karl Rove, have spent more than $1 million on independent ads and other boosts for House GOP candidates in New York, Nevada and Arizona. Spokesman Nate Hodson says they plan to spend "tens of millions" more by Election Day. Other groups helping House Republicans include the Congressional Leadership Fund associated with House GOP leaders, the YG Action Fund founded by aides to House Majority Leader Eric Cantor, R-Va., and the Chamber of Commerce.

Democrats are getting assistance from the House Majority PAC connected to House Democratic leaders, the Service Employees International Union and the League of Conservation Voters. But they are expected to be significantly outspent by their GOP rivals.

"They don't have to make decisions" about where to spend campaign funds, House Minority Leader Nancy Pelosi, D-Calif., told reporters recently. "They have an endless spigot."

Countering that Republican advantage is the 63 seats they took away from Democrats in 2010, when conservatives streamed to the polls motivated by their hatred of Obama's health care overhaul. GOP strategists acknowledge that some of those new members represent vulnerable districts that historically trend Democratic.

The competition stretches from coast to coast.

California and New York each has nearly 10 seats in play. Illinois, Florida and North Carolina also feature several tight battles. Even solidly Democratic Massachusetts and ruby red Texas each has a competitive race. Rep. Francisco Canseco, R-Texas, is running in a redrawn district that is less friendly to Republicans and Rep. John Tierney, D-Mass., faces a tough challenge from Tisei.

States have redrawn their congressional district lines to reflect the 2010 census, but analysts say neither party was advantaged overall. Redistricting did produce 19 new seats in which no House veterans are running, plus five others where incumbents are squaring off: two in California and one each in Iowa, Louisiana and Ohio.

Democrats are virtually certain to lose districts they now hold. They probably will need to capture more than 30 current GOP seats to cement a net pickup of 25.

Seats vacated by retiring Democrats in Arkansas, Indiana, North Carolina and Oklahoma seem likely to fall into Republican hands. Reps. John Barrow of Georgia and Larry Kissell of North Carolina, among the dwindling number of white Democrats representing Southern states, are in difficult re-election bids.

Democrats have strong prospects in Illinois, New Hampshire and Maryland. GOP House members struggling to keep their seats include Rep. Charlie Bass, R-N.H., and freshmen Reps. Joe Walsh and Robert Dold in Illinois.

Republican ads link Democrats to Obama, blaming them for the economy's painfully slow recovery, the job shortage and the health care law. One such ad by the NRCC attacks Barrow for supporting Obama's stimulus bill and voting to raise the government's borrowing limit last year.

"John Barrow—his loyalty to Obama is hurting America," it says, showing pictures of the two men.

Democrats accuse Republicans of trying to kill Medicare and shower the rich with tax cuts, hurting the middle class by cutting education and diminishing women's rights by seeking to curtail abortion. They refer frequently to GOP vice presidential candidate Paul Ryan, the House Budget Committee chairman whose recent spending blueprints have proposed reshaping Medicare and slicing taxes across the board.

"Mitt Romney grabbed the megaphone for us when he chose Paul Ryan," said Rep. Steve Israel, D-N.Y., who heads the DCCC. "He branded this debate and gave us the debate he wanted."

As for Romney's problems, including the secretly recorded video in which he said almost half the country is dependent on government, GOP leaders are studying the impact on House races but "no panic button is being pushed yet," said Rep. Steven LaTourette, R-Ohio.

"I continue to feel confident about House Republicans' chances of holding onto our majority," House Speaker John Boehner, R-Ohio, told reporters.