(CNN) - It's one of the biggest questions in 2013 campaign politics: Will former Sen. Scott Brown of Massachusetts make a bid this year to return to the Senate?
A source close to the Bay State Republican tells CNN Thursday that "Scott is undecided. I think he's going to wait for an actual vacancy to be declared and for an election date to be set."
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The vacancy will most likely happen later this month or early February, when the Senate is expected to confirm one of its own, John Kerry, as secretary of state. Last month President Barack Obama nominated the longtime senator from Massachusetts and 2004 Democratic presidential nominee as his choice to succeed outgoing Secretary of State Hillary Clinton.
Depending on when Kerry steps down from the Senate to take over as secretary of state, a special election to fill his seat would take place in mid to late June or July. The state's Democratic governor, Deval Patrick, would name a placeholder (who would not run in the special election) to fill the seat in the interim.
In January 2010, then Republican state lawmaker Brown upset Democratic candidate Martha Coakley, the state's attorney general, in a special election to fill the final two years of the term of longtime Democratic Sen. Ted Kennedy, who died the previous summer.
Brown won the special election by five points over Coakley, but lost his re-election bid in November to Democratic challenger Elizabeth Warren by eight points. Around 2.3 million voters cast ballots in the 2010 special election, and nearly 3.2 million voting in last month's general election. A big question is whether the 2013 electorate will look more like that of the 2010 contest or that of last month's general election.
In his Election Night concession speech Brown in November said "defeat is only temporary."
And in his Senate farewell speech last month, Scott repeated that line, and also added that "depending on what happens, and where we go, all of us, we may obviously meet again, but I'm looking forward to continuing on with those friendships, with continuing on working with my staff."
Longtime Democratic Rep. Ed Markey announced his candidacy late last month. He has been endorsed by Kerry, Ted Kennedy's widow Vicki, and by the Democratic Senatorial Campaign Committee, which is hoping to avoid a primary. Rep. Stephen Lynch, a social conservative from South Boston, is flirting with running, and Rep. Michael Capuano is also considering a bid, but some political strategists in Boston say he's not likely to run.
Even though they voted him out of office in the November election, 58% of Massachusetts voters questioned in a WBUR poll conducted last month said they have a favorable opinion of Brown, with just 28% saying they viewed him in a negative light.
According to the poll, Brown grabbed the backing 47% of registered voters compared to 39% who said they would vote for a generic Democratic candidate in a 2013 special election contest. The survey also indicated Brown with double digit leads against Markey, Capuano, and Lynch, in hypothetical matchups.
Whoever wins the special election would serve the final year and a half of Kerry's term and would then have to run again in 2014 for a full six-year term in office.