RUTHFULLY YOURS

By NAFTALI BENDAVID

Both parties are pouring in money and dispatching heavy hitters in advance of a May 18 special election in western Pennsylvania, a race that could provide important signals about the outcome of the November elections.

Associated Press In campaign mode in Pennsylvania, Republican Tim Burns, above, and Democrat Mark Critz, below. They seek the U.S. House seat once held by John Murtha.

Democrat Mark Critz, a longtime aide to the late Rep. John Murtha, is facing off against Republican businessman Tim Burns as they vie to succeed Mr. Murtha. The winning party will be able to claim a morale-boosting victory as the campaign season heats up.

Former President Bill Clinton is visiting the district this weekend to campaign for Mr. Critz. Sen. Scott Brown (R., Mass.), who won his own special election in a Democratic area, plans to stump for Mr. Burns Friday.

The district, sprawling across nine counties, is a classic swing area. It is the only district in the country to support Democrat John Kerry for president in 2004 and switch to Republican John McCain in 2008. Democrats outnumber Republicans there, but many of those Democrats are conservative on social issues, favoring gun rights and a strong military.

“If a Republican takes Jack Murtha’s seat in a district with a 2-to-1 Democratic edge, I would say that is a serious message to Democrats in moderate to conservative districts,” said Joseph DiSarro, chairman of the political science department of Washington & Jefferson College in Washington, Pa., which is in the district.

But if Mr. Critz pulled off a win, it would enable the Democrats to claim they stopped the GOP’s momentum, which has been building for months.

Associated Press

President Barack Obama has struggled to reach voters like these, and his infamous bowling excursion in the 2008 campaign, where he scored a meager 37 on a trip that attempted to burnish his blue-collar credentials, was in nearby Altoona. These voters are wary of the Democrats’ agenda and will be key to many of November’s congressional races.

“This is a gun-owning, blue-collar southwest Pennsylvania district that has sent a Democrat to Congress for decades,” said David Wasserman, who follows House races for the Cook Political Report. “If the Republicans win, they will have turned a big corner.”

Adding to the Democrats’ anxiety is a likely loss in a Hawaii district that includes Honolulu. It is a Democratic area, but two Democrats appear to be splitting the vote in the winner-take-all election.

In a recent Honolulu Advertiser poll, Republican Charles Djou, a city councilman, was favored by 36%, while Democratic former Rep. Ed Case was backed by 28% and state Senate President Colleen Hanabusa, a Democrat, had 22%.

A Republican victory in the May 22 election would provide a symbolic boost to the GOP nationally, not least because Hawaii is Mr. Obama’s home state. And it could make it easier for Republicans to gain the 41 seats they need to take control of the House, though Democrats say they would have a good shot at retaking the seat in November

But the Hawaii one may not be a bellwether for November. It is a mail-only election, and in the fall’s races two candidates of the same party won’t be able to split the vote.

The Pennsylvania race, in contrast, could send signals about the coming fight for Congress. It is unfolding in a district Mr. Murtha represented from 1974 until his death in February, and his crusty personality and pro-defense policies in many ways personified the region.

His would-be successors have very different messages. Mr. Critz, the Democrat, touts his time as an aide with Mr. Murtha and his knowledge of the district, while the GOP’s Mr. Burns, who has organized tea-party rallies, cites his business credentials as founder of a pharmacy technology company.

“This race is no longer about John Murtha,” Mr. Burns said in an interview. “It’s literally a referendum about the Obama-Pelosi agenda and this health-care bill. People are very upset that the health-care bill got passed.”

While Mr. Burns emphasizes national issues, Mr. Critz is distancing himself from the national Democratic Party. “Nothing is more important than jobs and economic development here in western Pennsylvania,” he said.

Mr. Critz also emphasizes his conservative credentials, calling himself “pro-life” and “pro-gun.” and touting his “A” rating from the National Rifle Association.

Democratic and Republican leaders, knowing the race will be seen as a political weather vane, are investing heavily in it.

The National Republican Congressional Committee, which coordinates GOP House campaigns, has sunk about $728,000 into the race. Republican leaders such as Newt Gingrich and Sarah Palin have endorsed Mr. Burns.

The Democratic Congressional Campaign Committee has spent roughly $641,000 to boost Mr. Critz. Vice President Joe Biden, who Democrats say connects well with working-class voters, has appeared on Mr. Critz’s behalf. House Speaker Nancy Pelosi (D., Calif.) has helped raise money for him in Washington—a fact his opponent has seized on. Mr. Critz retorted that the race isn’t about Ms. Pelosi but about western Pennsylvania.

Both sides, but Democrats in particular, are playing down expectations. Democrats note that Mr. Obama’s approval ratings in the district are below 40%.

Polls on the race vary, but participants agree it is tight. A poll released Wednesday conducted for the Pittsburgh Tribune-Review by Susquehanna Polling & Research showed Mr. Critz leading Mr. Burns 44%-38%.

The campaigns have exchanged hard-hitting television ads. Mr. Critz accuses Mr. Burns of outsourcing jobs and says the Republican wants to privatize Social Security, both of which Mr. Burns denies. Mr. Burns accuses his rival of being a Washington insider, a characterization Mr. Critz rejects. These broad themes are likely to be repeated across the country as the campaign season heats up.

“It’s an outsider versus an insider,” said NRCC spokesman Tory Mazzola. “That is a narrative that will be blasted continuously until November.”

Write to Naftali Bendavid at naftali.bendavid@wsj.com