First, I'm not 100 percent sure outgoing Sen. Scott Brown is going to run for Senate instead of running for governor. Being governor means actually having to do work; being in the Senate means you can just fart around and tout bi/nonpartisanship and independence, at least for a while. On the other hand, it's much, much easier to get elected governor, and, in particular, to get reelected—you can claim to have no ties to the national GOP and that, as we know Brown likes to do. If he's in the Senate he'll be hunted this spring, in fall 2014, and then every six years—and he'll occasionally have to fight Presidential-year turnout, as he did in 2012. Now that everyone knows he can be beat, people won't be scared to take him on as they were in 2012; he might be able to hold back the tide in midterm elections.
If Brown doesn't run, former Gov. Bill Weld, who just moved back to the state, actually might. That would also be a tough race, but less so than Brown. Weld was an immensely popular governor, but he last held office during the Clinton administration, he moved out of state for several years, and he lost his last race (a 1996 Senate bid against John Kerry himself).
Gov. Deval Patrick has said a million times he's not interested in the Senate. I'm inclined to believe him, though he'd be a strong candidate if he ran. Patrick apparently wants to appoint Vicki Kennedy. She's not categorically refusing as she's done in the past, but she's also far from a sure bet to take an appointment, and if she were appointed as a caretaker, it's not certain she'd run to succeed Kerry.
Beyond that, what does the field look like?
- Rep. Ed Markey is old, at 66, for a first-time Senate candidate, but still kind of feisty, and he can somewhat emulate what Sen.-elect Elizabeth Warren did because he's quite focused on a particular issue that polls well in Massachusetts (environmental regulation). However, it's not clear Markey has the stomach for a really tough race at his age (he opted against a run in 2010). He's sitting on $3 million right now, which would give him a nice leg up.
Markey is also uniquely well positioned to make an argument that worked for Warren—not just being strong on environmental issues but being a leader (in Warren's case there was no doubt she'd be a leader on financial issues). One of Brown's big weaknesses was that while he was seen as a nice guy, he was never a titan—no one points to any big issues that Brown is a leader on, because there aren't any. And whatever legislative accomplishments Brown has, they pale in comparison to Markey's.
- Former Rep. Marty Meehan seems to like his job as chancellor of UMass Lowell. But he's still sitting on a pile of money he'd saved for just such a race, and starting with close to $5 million squared away, he'd look pretty good in a special election.
- Rep.-elect Joe Kennedy III has said he won't do it, and while he might change his mind, that's probably wise. He's an insanely good fundraiser and he raised Senate money for a House race. But he's just 32, his resume is great for a 32 year old (Stanford, Peace Corps, Harvard Law, prosecutor, Congressman), but thin for a Senate candidate, especially as he hasn't even been sworn in. He's going to run for governor or Senate some day, just not now.
- Rep. Mike Capuano might get in. He's very liberal, and aggressive enough to take the fight to Brown. But it's hard to gauge his strengths as a candidate—he lost the primary for the last special election to Attorney General Martha Coakley, he didn't raise that much money, and has never had a tough race since he was elected to Congress with 23 percent of the primary vote in 1998. On the other hand, he might benefit from buyer's remorse from the 2010 special election, and if he can raise enough money for a big race, his profile—he could run easily as a progressive fighter for the middle class, as Elizabeth Warren did—would fit the state well.
- I doubt Rep. Stephen Lynch will run. He could have in 2010 and chose not to. I think he wants to be a Senator, but Lynch, who is actually very bright, knows his limitations; he'd have a hard time fundraising from Democrats because he's pro-life and generally more conservative, and any success he'd have peeling off blue-collar workers from Brown would be more than cancelled out by bleeding support among suburban women and Democrats generally not showing up. You need high turnout to beat Brown and Lynch won't get that.
- Martha Coakley and state Treasurer Steve Grossman are mentioned (Grossman could bring a lot of money to a race, as he's the former DNC Chair), but I think both of them are running for governor. (Coakley, by the way, would be a strong candidate for governor, as she's still popular within the state and has earned praise for her work as Attorney General).
- US Attorney Carmen Ortiz is a total wild card. Deval Patrick loves her. She's made a name investigating Beacon Hill politicians, which actually helps distinguish her from the "Democrat machine" Brown likes to rage against, but it might cost her institutional support in the city—and again, you need really high turnout for a June special. She's never run for elected office as far as I know, so who knows if she can raise the money she'd have to raise to beat Brown—but if she can, she's got a good profile.
- Alan Khazei has had his chances to show he can get traction. He's failed so far.
- Rep. Richie Neal is unlikely to give up a seat on Ways and Means especially since no one outside Western Massachusetts knows who he is. Also, Rep. Jim McGovern, who could run well in Worcester, is thought to want desperately to be Rules Committee chairman, a position from which he's not far away.
- Wild cards abound, of course: there could be some random rich people who get in (as Celtics part-owner Steve Pagliuca did in 2010), or it could be a relatively low profile mayor (Kim Driscoll of Salem, who is supposedly running for lieutenant governor; Scott Lang of New Bedford, who might struggle with labor support); or a member of the state House or Senate (Ben Downing, who is a 31-year-old four-term State Senator).
- We also have a lot more law professors in Massachusetts.
A special election for Senate in Massachusetts is going to remain a scary thing for Democrats nationally since the debacle of January 2010, and as Markos mentioned, the Democratic candidate in a potential special election in 2013 would not have the ammunition Elizabeth Warren used so well in 2012, that the balance of power in the Senate was in play. That said, Massachusetts Democrats have done a lot to get their act together since January 2010, and 2012 highlighted many Scott Brown weaknesses that a Democratic nominee could still exploit in 2013.