Sen. Hillary Rodham Clinton’s (N.Y.) latest pitch in her come-from-behind bid for the Democratic presidential nomination is that she runs considerably stronger in Republican-leaning House districts than does rival Sen. Barack Obama (Ill.).

Trailing Obama significantly in the race for pledged delegates, Clinton is aiming to sway the freelance Democratic Party superdelegates who can vote for any candidate at the nominating convention in late August.

The Clinton campaign, arguing that the New York Senator is the more electable candidate nationally against the presumptive GOP nominee, Sen. John McCain (Ariz.), pointed out to reporters Friday morning that she has beaten Obama in 16 of 20 House districts that went for President Bush in the 2004 presidential race but are now held by a freshman Democratic Member.

“That is a dramatic difference in how Sen. Clinton runs in these key, battleground districts,” Clinton campaign spokesman Howard Wolfson said at an event sponsored by The Christian Science Monitor. “As a former executive director of the DCCC, I would feel more comfortable with somebody who runs stronger in the kind of competitive districts Democrats will be competing in Congressionally in 2008.”

This contention was bolstered in an open letter to superdelegates that was signed by 16 House Democrats, including freshman Reps. Michael Arcuri, Kirsten Gillibrand and John Hall, all of New York; freshman Rep. Joe Sestak (Pa.); and Reps. Ike Skelton (Mo.) and Debbie Wasserman Schultz (Fla.).

“Hillary has won rural and suburban districts which we as Democrats must carry to maintain our edge in Congress,” these Members wrote in the May 8 letter, which was publicized on Friday.

The 16 districts Clinton is using to boost her electability argument — seats won by Bush in 2004 but where the Democratic House candidate won in 2006 — include Arizona’s 8th, California’s 11th, Florida’s 16th, Indiana’s 2nd, 8th and 9th, North Carolina’s 11th, New Hampshire’s 1st, New York’s 19th, 20th and 24th, Ohio’s 18th, Pennsylvania’s 4th and 10th, and Texas’ 22nd and 23rd.

Four such districts that Obama won over Clinton include Arizona’s 5th, Kansas’ 2nd, Minnesota’s 1st and Wisconsin’s 8th.

The Obama campaign did not immediately respond to a request for comment, but the Democratic Congressional Campaign Committee expressed zero concern that an Obama candidacy would hamper the prospects of its candidates this fall.

“The energy, excitement and new voters generated by both Sens. Obama and Clinton will only serve to benefit our House candidates,” DCCC spokesman Doug Thornell said. “We much prefer to be in our shoes than in the Republicans’ shoes. They are hitching their wagon to a third Bush term.”

One superdelegate who declared for Obama on Friday predicted Clinton’s sales pitch would fall short.

Ed Espinoza, a Democratic operative and Democratic National Committee member from California, said superdelegates like himself are likely to factor in Clinton’s argument that she runs stronger in Republican-leaning districts and would offer more coattails to downballot Democrats.

But, Espinoza said, that argument is not likely to carry enough weight with superdelegates to change a race that finds Obama ahead in pledged delegates with less than a month to go in the primary contest, and at virtual parity with Clinton among superdelegates.

“I think at one point [her argument] may have been compelling. But at this point it’s less so,” Espinoza said. “You’re dealing with a Democratic electorate. She may have won over a bloc of them in the primaries, but that doesn’t mean that bloc is not going to vote for the ticket in the fall.”