There have been a few extra out-of-towners wandering in New Jersey this summer: political leaders intent on helping their party win the Third Congressional District race.

On Monday, U.S. Rep. Joseph Crowley (D., N.Y.) drove the New Jersey Turnpike, listening to Bruce Springsteen and Jon Bon Jovi on his way to a Mount Laurel firehouse to endorse the Democratic candidate, State Sen. John Adler.

The next day, U.S. Rep. Debbie Wasserman Schultz (D., Fla.), a top party campaign official, was the draw at a Woodcrest County Club fund-raiser in Cherry Hill for Adler.

Also Monday, at Medford's historic Braddock's Tavern, U.S. Rep. Roy Blunt (R., Mo.), the House Republican whip, and U.S. Rep. Tom Cole (R., Okla.), chairman of the National Republican Congressional Committee, held an evening fund-raiser for the GOP candidate, Medford Mayor Chris Myers.

Other party leaders have come and gone, and more are penciled in for fall visits. It is also likely that independent political groups will make their views known. The conservative Freedom's Watch targeted Adler with telephone calls this month blaming him for the high cost of gasoline; Adler has campaigned on lowering the cost.

Why all the attention?

This traditionally Republican district, which includes parts of Burlington and Ocean Counties and Cherry Hill in Camden County, is in play this year, with both parties promising a fierce battle over it.

The seat opened up with the retirement of U.S. Rep. Jim Saxton (R., N.J.). A seat in the central part of the state, held by retiring U.S. Rep. Mike Ferguson (R., N.J.), also is in play, making New Jersey one of the most-watched states for congressional scorekeepers. Most analysts are expecting Democrats to hold onto their House majority and pick up more seats, most likely in New Jersey.

"It's significant when you have two open seats in a state the size of New Jersey and both are potentially turnover seats," said University of Virginia political scientist Larry Sabato. He has both rated as toss-ups but said, "I'll be surprised if the Democrats don't pick up at least one of the two."

Democrats targeted the Third District race as a possible takeover early and fielded Adler, who ran for the seat in 1990 but lost to Saxton. In the Seventh District, which runs from Hunterdon to Middlesex Counties, Democrats have had Assemblywoman Linda Stender (D., Union) in place since she lost by one percentage point to Ferguson in 2006. She faces State Sen. Leonard Lance (R., Hunterdon) in the fall.

The party's campaign arm, the Democratic Congressional Campaign Committee, has helped Adler and Stender with fund-raising and expertise.

Schultz, who helped Adler host a fund-raiser this week, co-chairs the party's program to flip Republican seats into Democratic ones. She is Adler's assigned mentor, helping him get endorsements from nonprofit groups and donations from political action committees that usually ignore nonincumbent candidates.

Schultz said Adler "is one of our most promising top-tier candidates in the country." She said Adler had met or exceeded the party's undisclosed goals for fund-raising and building a volunteer organization.

In contrast, Republicans got into this game later than the Democrats. Saxton did not announce his retirement until November, and there was not a clear nominee until June 3 because of a bitter primary campaign.

The national party was unwilling to take sides in that primary race between Myers, backed by the Burlington County GOP, and Ocean County Freeholder Jack Kelly, backed by his county's machine.

Myers' campaign says the county organizations have made peace, but others question how much Ocean County's machine can do for Myers.

Not only did the Ocean County GOP lose the congressional race, but its down-ballot candidates for county offices took a serious challenge from an organized group of disgruntled Republicans.

Beyond that, "it is possible this is no longer a Republican district, and this election might show that," said Patrick Murray, director of Monmouth University's Polling Institute, adding that he is seeing similar subtle changes in the Seventh District.

Both districts have seen an influx of residents from more urban areas of the state - residents who tend to vote for Democrats, he said.

David Wasserman, a native of New Jersey who rates races for the nonpartisan Cook Political Report, has the seats listed as Republican toss-ups, because they are now held by Republican congressmen.

Wasserman cautioned that the Adler-Myers race could go either way.

Noting that President Bush lost among voters in the Third District in 2000 but came back to win in 2004, he said, "This is a district that is open to the right kind of Republican."

Looking at the uncertainty surrounding the fate of both House seats, he said, "These are going to be very close races and, I think, marquee battles between the parties."

Contact staff writer Cynthia Burton at 856-779-3858 or cburton@phillynews.com.