Paul Blumenthal writes at The Huffington Post:
Sen. Mark Pryor (D-Ark.), who faces the Senate's toughest reelection, spent the final days of June shooting campaign video -- for an election still more than 16 months away.
Independent groups spent $1.1 million in 2014 general election Senate campaigns in Arkansas and Kentucky during the first six months of this year, 11 times the $100,000 the groups had spent at this point in 2011.
Despite questions about donor fatigue and notable super PAC bets on losing candidates in 2012, independent group campaign spending is off to the fastest start ever in next year's Senate races, according to campaign finance records. The onslaught of spending is forcing candidates like Pryor to start campaigning earlier than ever, pushing the election calendar farther back and propelling incumbents and their challengers to raise even more money to start their campaigns early.
Club for Growth Action, the super PAC of the conservative Club for Growth, was the first group to go up against Pryor with an ad in February telling Arkansas voters, "When you vote for Pryor, you vote for Obama."