Former Senator Scott Brown announced today that he will not run in a special election, scheduled for June 25, that will decide the permanent Senate replacement for soon-to-be Secretary of State John Kerry. The decision is understandable — he reportedly wants to run for governor of Massachusetts, and just emerged from a bruising defeat to Harvard professor Elizabeth Warren. But Brown's surprise move comes at a heavy price to his party: There is no equally popular Massachusetts Republican to replace Brown, and even a closer race among Democratic candidates makes stealing Kerry's seat for the GOP look like a long shot now. Here are the three most likely scenarios of what will happen next.

Another Republican emerges

Yes, an unknown Republican could still come out of the blue red and win — much like Scott Brown in 2009! As for possible contenders, The Boston Globe lists William Weld (a former Governor of Massachusetts), Kerry Healey (a former lieutenant governor), Gabriel Gomez (a former Navy SEAL), and Daniel Winslow (a former state representative and friend of Mitt Romney). The problem with this scenario has nothing to do with the competence or star power of these candidates ... and everything to do with Massachusetts Democrats. Remember, a major reason why Brown won in 2009 — in a special election following the death of Ted Kennedy — was the well-documented incompetence of Martha Coakley's campaign staff. It wasn't just that Brown was a decent, likable guy; he also faced a completely disorganized opposition. Elizabeth Warren's November victory suggests state Democrats won't let that happen again.

Stephen Lynch challenges Ed Markey

Yesterday Congressman Stephen Lynch, a pro-life Democrat who opposed the passing the Affordable Care Act, entered the race. His positions are distinct enough to pose a challenge to Markey, a generic blue-state Democrat, plus Lynch could attract conservative voters who would have otherwise supported Scott Brown. The dynamics of Lynch's campaign are difficult to assess so early on, but it's certainly possible he'll collect a bunch of independent voters who would have otherwise gone for Brown — or at least diminish some of the overwhelming support for Lynch thus far.

Markey sails to victory

Again, it's too early on to see if Lynch makes for a formidable opponent. But it's not too early on to note that Markey is already supported by many, many Massachusetts Democrats — including John Kerry — and has built a campaign staff capable of electing him. (He recently hired two of Elizabeth Warren's former staffers.) With Brown out of the running, Markey's biggest challenge will be convincing his own party that he, not Lynch, ought to preserve its legacy in the U.S. Senate.

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J.K. Trotter