While even Republicans concede that Massachusetts Sen. John Kerry will emerge from the Democratic convention with some sort of bump in the polls, whether that energy trickles down to Democrats running in Senate and House races remains an open question.

Congressional Democrats entered the convention on something of a high, buoyed by recent fundraising successes that put them at near parity with their Republican counterparts. A handful of recent generic Congressional ballot surveys that show voters prefer a Democratic candidate by anywhere from 9 to 16 points.

At a Tuesday morning briefing designed to introduce top Senate candidates to high-dollar donors, Democratic Senatorial Campaign Committee Chairman Jon Corzine (N.J.) said that the convention is unquestionably beneficial to Democratic candidates.

“To the extent our candidates get to speak in front of larger audiences, it sends people back to their states with not only better fundraising contacts but also more excitement,” he said.

Sen. Patty Murray (Wash.), who chaired the DSCC in 2002 and is one of a handful of targeted incumbents this cycle, is leaving Boston today to return home and host a viewing party of Kerry’s official nomination Thursday.

The convention, she said, “is focusing people on the fact that we are less than three months out and what’s at stake in this election.”

Democratic Congressional Campaign Committee Chairman Robert Matsui (Calif.) offered an opposing perspective, arguing that the convention has little impact on the fight for control of the House because “the focus is on the presidential race.”

“We think our work is more incremental,” he said. “It is more like three yards and a cloud of dust rather than a big bounce.”

Led by Kerry, Democrats are laying out their agenda this week to keep America both safe and prosperous. The Massachusetts Senator has also suggested that members of his party avoid simply bashing President Bush, a suggestion that has been barely heeded — if at all — to date.

“If people feel good in a general context that the Democratic Party will be strong on the economy and strong on defense, it spins to the benefit of our candidates across the country,” Corzine said.

The problem for the party — and its candidates — is that while the convention provides them with a bully pulpit the likes of which they are unlikely to see again this election, the message coming out of Boston is not necessarily a winning one for some candidates in tight races in this election.

This dichotomy was evident at the Tuesday morning DSCC briefing, where Oklahoma Rep. Brad Carson, former White House Chief of Staff Erskine Bowles (N.C.) and former Alaska Gov. Tony Knowles were missing. All three have been highly touted by the campaign committee.

In the Senate, Democrats must defend five of their own seats in the South, none of them in states that Kerry is favored to win in the fall. They also must win in the Republican strongholds of Oklahoma, Alaska and South Dakota if they hope to retake the body they lost in the 2002 election.

Louisiana Sen. John Breaux (D), who is retiring at the end of the year after three terms in the Senate, said that the impact of the Democratic and Republican conventions on the race to replace him is likely to be minor.

“Ultimately, most voters won’t go to Boston or New York,” he said. “The convention gives a candidate a chance to present himself to national donors but ultimately the race is about Louisiana.”

The road to the House majority also goes through the South, where Democrats’ narrow chances of winning back the body likely hinges on their ability to re-elect the five Texas Democrats who are seriously endangered by a Republican-led redistricting plan signed into law last year.

House Democrats have pointed to their standing in the generic ballot as a sign that voters are receptive to their message and will grow more so as the convention, and election, continue, exposing more people to the party’s ideals.

But, even on that point, leading party strategists remain divided.

Alan Secrest, a Democratic pollster handling a number of competitive House races, predicted that not only will downballot candidates get a bump from the convention but that it will also be sustained by their message.

“While the boost will be incremental, it is likely to be both measurable and sustained, particularly since Kerry — and the convention as a whole — will be speaking directly to swing voters’ concerns,” he said.

Democratic media consultant Anita Dunn conceded that while the generic ballot test may “bounce a little [after this week], candidates generally don’t get a convention bounce below the presidential level.”

Arkansas Sen. Mark Pryor (D) agreed, noting that while the convention provides a platform for all Democrats, “a lot of these races turn on local issues.”