Eric Holder is back on Capitol Hill, voters in Arizona choose a successor for Rep. Gabrielle Giffords, plus more to watch for Tuesday in politics

— -- Attorney General Eric Holder will be back on Capitol Hill on Tuesday, testifying before the Senate Judiciary Committee the day after the House Oversight and Government Reform Committee announced it will vote June 20 on whether to hold him in contempt. The contempt vote is related to the investigation into the "Fast and Furious" gun-walking operation, which Holder testified about before another House committee on Thursday.

In Arizona, voters will go to the polls to choose a successor for Rep. Gabrielle Giffords, who gave up her seat in Congress in January to focus on her recovery from a gunshot wound to the head. A poll that came out Monday showed Giffords' former aide, Democrat Ron Barber, with a 12-point lead over Republican Jesse Kelly, who narrowly lost to Giffords in 2010. The victor in Tuesday's race won't have much time to celebrate, though — it will soon be back to campaigning, as the winner will need to win election to a full term in November.

Another man hoping to win an election in November, Mitt Romney, will be campaigning in the battleground state of Florida on Tuesday, while President Barack Obama will attend fundraisers in Maryland and Pennsylvania.

New Jersey Gov. Chris Christie, a possible vice presidential pick for Romney, will hold a town hall meeting in Haddonfield, where, in 2009, Romney endorsed Christie for governor. This will be Christie's first trip back there since the endorsement.

In Chicago, Vogue editor Anna Wintour and Obama's campaign manager Jim Messina will be at Oprah's TV studios hosting a fundraising event for the president's re-election bid. Called "Runway to Win," the event will also feature the models Iman and Chanel Iman.

Michelle Obama will be in D.C. on Tuesday, signing copies of her new book, "American Grown: The Story of the White House Kitchen Garden and Gardens Across America," at a local Barnes & Noble.

And then there is this: Tuesday is the 25th anniversary of President Ronald Reagan traveling to Berlin and challenging Soviet leader Mikhail Gorbachev to "tear down this wall." The Berlin Wall fell on Nov. 9, 1989.

Sources: Yahoo News, Associated Press