Staying out of the fray. For now.

Some Democratic leaders who have not yet endorsed a candidate are holding their cards close to the vest. The Hill reports that many of them (are there many left who are still uncommitted?) are beginning to wonder if Barack Obama can carry this through. What a difference a couple of weeks make.

Despite Sen. Barack Obama’s (D-Ill.) promises, many Democratic congressional candidates in conservative districts remain unconvinced that he can redraw the general election map by competing in red states.

While Obama is popular among some challengers seeking an edge in contested primaries, other non-incumbents have shied away from endorsing him. Most are staying out of the fray, endorsing neither Obama nor Sen. Hillary Rodham Clinton (D-N.Y.).

What this is about, is that whole set of other races the mainstream media aren’t covering, at least yet. Or hardly mentioning, though this analysis reveals why it’s so interesting to figure in the fall elections of congressional candidates, and how they see the contest for their party’s presidential nomination.

The situation is unusual because of how late in the cycle the nominating contest has endured and how early many races have taken shape. This has given more candidates the opportunity to offer endorsements that could affect the senators’ presidential hopes and their own congressional campaigns.

But few have taken the bait.

Prudently, they’re showing appreciation for both Obama and Clinton and generally playing it safe.

“It’s not as if my viewpoints ideologically align neatly with any one candidate,” said Ohio state Rep. Steve Driehaus, who is challenging Rep. Steve Chabot (R-Ohio). “I think they all bring value to the table. We’re going to work with whomever the nominee is, but we’re focused on winning this congressional seat.” …

Similarly, North Carolina congressional candidate Larry Kissell, who has a clear primary path to face Rep. Robin Hayes (R) for the second straight cycle, is staying neutral. He initially supported the former Tar Heel State Sen. John Edwards (D-N.C.), but he won’t make a second endorsement.

The big issue is the crossover vote, which of the presidential candidates is more likely to draw voters from the opposite party. Several congressional candidates cited here consider Obama the more appealing to a wider electorate. But that view has been up for grabs in the past two weeks, making for daily speculation and poll watching.

Crossover appeal isn’t only on the minds of the Democrats.

Republicans are dubious about Obama’s actual appeal to GOP voters, pointing to polls that show GOP nominee Sen. John McCain (Ariz.) taking more Democratic votes than vice versa.

They have also played up the recent National Journal article that ranks Obama’s voting record as the most liberal in the Senate.

“The Senate’s ‘most liberal’ member cannot hope to run well among independents and conservatives on a typical Democratic platform of higher taxes and bigger government,” Republican National Committee spokesman Alex Conant said Monday.

This is getting the feel of the Kentucky Derby buildup. And it’s not even April.