Some of Bernie Sanders' top supporters are promoting Oregon Sen. Jeff Merkley as Hillary Clinton's running mate.
They say that Merkley — the only senator to back Sanders — would help unify the party and doesn't have the political downsides of some more prominently mentioned candidates.
The idea of Merkley as the Democratic vice president pick gained additional prominence Tuesday in a column authored by Robert Borosage, who has led several Democratic left groups and was a top issues advisor for Jesse Jackson's 1988 presidential campaign.
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"His presence would excite the young and independent voters that were at the heart of the Sanders vote," Borosage wrote for the website run by the group he helps lead, the Campaign for America's Future.
"It would reassure skeptical labor activists," Borosage added. "[Merkley] would add credibility on trade, on investment, on Wall Street reform, on money and politics and on climate, all areas where doubts linger about Clinton’s commitment."
Merkley has not been prominently mentioned as a likely running mate for Clinton. He is not well-known outside of Oregon and doesn't have the charisma of Massachusetts Sen. Elizabeth Warren, perhaps the most talked about running mate for Clinton.
Borosage said in an interview that he hopes to drum up interest in Merkley as a VP pick who would both excite the Democratic left while avoiding the problems of some of the other choices. Borosage said he doubted that Warren would even want to be vice president under Clinton, and there are well-publicized doubts about whether Clinton sees her as someone who would be a good team player.
Ohio Sen. Sherrod Brown is another favorite of left-of-center Democrats, but he'd cost his party a seat in the Senate for at least two years if he became vice president. That's because Republican Gov. John Kasich of Ohio would get to appoint a replacement for the period through the 2018 election.
In addition, Clinton has shown no interest in picking Sanders himself. Merkley could serve as a more mainstream alternative.
Larry Cohen, a former president of the group Communications Workers of America, is a senior Sanders adviser, and acknowledged Merkley isn't well known among average voters. But he starts with a certain cachet as the only senator to endorse Sanders, according to Cohen.
Related: Merkley Explains His Endorsement Of Sanders
"He is certainly known to the hundreds of thousands of Bernie volunteers, and because of that, he would spark the 12 million Sanders voters like no one else," said Cohen, adding that picking Merkley would "be huge to Bernie himself."
Former Labor Secretary Robert Reich has also talked up Merkley as someone who could energize voters who are otherwise not excited about Clinton.
Merkley was traveling Tuesday and not available for comment. But in the past he has deflected questions about joining the presidential ticket by saying he sees other more likely candidates, such as Warren. There also hasn't been any talk from the Clinton campaign that he's on her short list for vice president.
But there are indications that Merkley doesn't mind the the VP mentions. He's worked hard to be known as a top Senate champion on a variety of liberal causes, from fighting Wall Street to championing efforts to reduce the use of fossil fuels to combat climate change. His brand has become strengthened by his ties to Sanders, and now by getting mentioned as a possible VP candidate.
The higher profile could help Merkley achieve one of his goals: getting picked to join the Senate Democratic leadership team after Senate Minority Leader Harry Reid of Nevada retires at the end of this year.