By Mike Riopell

Democratic governor candidate J.B. Pritzker's campaign on Monday unveiled a web video featuring Barack Obama, marking another foray into his home state's politics for the former president.

In the 90-second spot, Obama speaks to the camera about Pritzker's work with nonprofits and technology incubator 1871 Chicago.

"I know J.B. I trust J.B. And that's who he is, someone who is always thinking about how he can make a difference," Obama said.

It's not a surprise that the former Democratic president would back Pritzker over Republican Gov. Bruce Rauner, and Obama this month released a list of endorsements that included Pritzker. The digital spot released Monday, though, gives the campaign another video to spread across the internet in the months before the November election.

Obama has gotten involved in state politics from time to time since heading to the White House, including backing Ald. Sophia King in her City Council race last year.

Pritzker supported Hillary Clinton over Obama in the 2008 Democratic presidential primary and was a national co-chair of her campaign. Pritzker's sister Penny, however, backed Obama's 2008 presidential bid and later became his commerce secretary.

In a March 2012 Bloomberg TV interview, Pritzker hesitated on supporting Obama's re-election efforts. "We'll have to wait and see. I don't know who the nominee's going to be on the Republican side," Pritzker said at the time.

Pritzker has faced heat over phone calls secretly recorded by federal agents between the influential Democratic donor and then-Gov. Rod Blagojevich discussing their futures and the ramifications of Blagojevich's authority to fill the Senate seat being vacated by Obama.

In one of the calls revealed by the Tribune, Pritzker expressed his preference for being state treasurer. In another, he pitched the idea of picking Illinois Secretary of State Jesse White to fill Obama's vacated Senate seat, in part because it "covers you on the African-American thing."

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