This much is clear: The only "R" that Sen. Gordon Smith wants attached to him this year is the third letter of his first name.

The Oregon Republican suggested in a TV ad (subscription) this spring that he'd work well with President Hillary Rodham Clinton. Recently, he ran a spot (subscription) showcasing support from former Rep. Elizabeth Furse, a liberal Democrat. And this week, Smith ventured even further across the aisle, launching an ad (subscription) that touts a warm and fuzzy compliment he drew from Barack Obama.

It's a moderate's time-honored strategy: Cozy up to your political opponents in states where they run the show and you're just lucky to be invited to the party. But Smith's move still raises a key question: In a year when both Obama and John McCain claim strong appeal among independents and crossover voters, will other GOP Senate candidates in swing states follow Smith's lead? If so, what does that say about McCain's appeal?

There are a half-dozen other Republicans running in purple-to-blue states who face a similar choice. Here's a look at their races and whether they're likely to steal a page from the Smith handbook.

• Sen. John Sununu of New Hampshire: Polls show Sununu trails Democrat Jeanne Shaheen badly in a rematch of their 2002 contest, partly because his party is losing its decades-long hold on voters. Still, Sununu is unlikely to throw McCain under the bus. During the state's first-in-the-nation primary, McCain drew strongly from the large bloc of independent voters here and is likely to do so again this fall. Obama faces some challenges in New Hampshire; he lost the state to Clinton in January and is still working to build ties to Democratic women, many of whom strongly back Shaheen. Trying to lock arms with Obama could destroy any chance Sununu had of appealing to those voters.

• Former Rep. Bob Schaffer of Colorado and Rep. Steve Pearce of New Mexico: Schaffer and Pearce (who, coincidentally, are running against Smith's Democratic cousins, Mark and Tom Udall) are relying far more on generating big turnouts from their party's conservative base than on courting independents or Democrats as they run to succeed Republican senators in increasingly competitive Western states. Unlike Smith, or maybe even Sununu, neither Schaffer nor Pearce has a long record of bipartisanship that would lend credence to an attempted Obama outreach.

• Sen. Susan Collins of Maine: Maine likes Obama, a lot. And Collins, like Smith, is one of the dwindling band of moderate Senate Republicans who have a record of working well with the new Democratic majority. She could easily toss Obama a bouquet without suffering backlash from local Republicans. But two things make it unlikely. First, she's not in much danger this fall (polls show her leading Rep. Tom Allen by daunting margins). Second, Collins has established her own identity in a state with an enduring appreciation for independent Republicans. While Democrats comfortably won the governor's office and both House seats in 2006, Republican Sen. Olympia Snowe was sailing to a 3-to-1 victory.

• Sen. Norm Coleman of Minnesota: Coleman faces a potentially tough race against entertainer Al Franken in a state that has backed the Democrat in every presidential election since 1972 (the party's longest-running winning streak). He's also never faced a real test of his statewide electability; in 2002, opponent Walter Mondale was ill-prepared for the rigors of a modern campaign when he stepped in after Paul Wellstone's death. It will be difficult for Coleman to dodge the GOP label because he's an honorary co-host of his party's national convention in September.

• Former Rep. Dick Zimmer of New Jersey: Zimmer is the Republican most likely to join Smith in attaching himself to the Obama brand. Zimmer, a former congressman and lobbyist with a moderate voting record, was drafted into a run by party bosses because of his centrist cred. He has already come out strongly against McCain on offshore oil drilling and distanced himself on issues like abortion rights and Iraq. Perhaps more importantly, he's running for Senate in a state Obama is likely to win comfortably.