Congressman Jesse Jackson Jr. has been stumping for months for Barack Obama’s presidential campaign. But when he delivers a prime-time address at the Democratic convention Monday, Obama’s candidacy may not be the only one he’s promoting.

Friday afternoon Jackson sent out an e-mail to supporters that confirms his interest in moving up to the Senate if Obama wins the presidency—though he tries to make it sound as if he’s just responding to popular will.

“When (and I do mean when) Senator Obama wins, his Senate seat will be left vacant,” Jackson says in the e-mail. “While rumors are swirling about who will be appointed to fill this slot, people are taking notice of the change we’ve created right here in the 2nd Congressional District. … As a national co-chair of Barack Obama’s presidential campaign, I’ve been working hard to generate support and enthusiasm for our Democratic nominee and our party. It’s clear now that others are working hard to generate support and enthusiasm to bring the change we’ve made in the 2nd District to the entire state.”

The e-mail then asks everyone to read a column by veteran politico Don Rose that presents Junior as the smartest and most likely Obama replacement.

Governor Rod Blagojevich would make the pick, and Rose argues that he wouldn’t gain much by naming other potential replacements like state attorney general Lisa Madigan, who would rather become governor; congresswoman Jan Schakowsky, whose reform-minded supporters probably can’t be persuaded to back the governor’s reelection bid in return; or former congressional candidate Tammy Duckworth, who already works in the Blagojevich administration. On the other hand, shoring up his African American base would give the governor a big advantage in a 2010 Democratic primary.

“After Obama, the rising star in black politics—with a degree of crossover appeal—is another congressman named Jesse Jackson Jr., who made his bones with many white voters by slapping down his dad a couple of times for bad-mouthing Obama,” Rose writes.

“This is an appointment that would play well in many circles and show high potential for keeping much of the black base intact for the guv’s re-election. Jackson could also be influential in preventing state Sen. [James] Meeks from jumping into race as a spoiler.

“Senator Jackson, I presume?”

Jackson’s office didn’t respond to a request for comment. But he doesn’t seem to be taking issue with anything Rose said. In his e-mail the congressman asks supporters to help change the country by electing Obama and donating to Junior’s own war chest. “Help us take this change statewide,” he says.