BOSTON (AP) — William “Mo” Cowan, a former top aide to Democratic Gov. Deval Patrick, was tapped by Patrick on Wednesday to serve as interim U.S. senator for Massachusetts until a special election is held to fill the seat left vacant by John Kerry’s confirmation as the nation’s new secretary of state.

Cowan, 43, became chief-of-staff to Patrick in 2010 after serving as chief legal counsel during the governor’s first term. He stepped down as Patrick’s top aide in December, though he remained on as a senior adviser through the filing last week of the governor’s state budget request.

He’ll serve until after the special election, scheduled for June 25. He said he was humbled by the appointment.

Patrick lauded Cowan for helping manage the state through the recession and said he had earned the respect of people throughout government.

“In every step, he has brought preparation, perspective, wisdom, sound judgment and clarity of purpose,” Patrick said while introducing Cowan at a Statehouse news conference.

Patrick and Lt. Governor Timothy Murray added that the friendly Cowan — who eschewed his trademark bow tie in favor of a traditional suit and necktie for Wednesday’s announcement — also brings “cool” to the job.

Cowan grew up in North Carolina and graduated from Duke University and Northeastern University’s law school. He was a partner in the prominent Boston law firm of Mintz Levin before going to work for Patrick.

Patrick had said that diversity would be an important consideration in his choice of an interim senator, and Cowan will be the state’s second African-American senator. Edward Brooke, a Republican, represented Massachusetts from 1967-1979.

Cowan said his mother, who is recuperating in North Carolina after knee-replacement surgery, was a child of the segregated south who raised him and his sisters alone after his father died when Cowan was a teen.

“My mother told me that days like today are possible if you work hard and you treat people with respect,” he said.

Cowan, who indicated that he would keep members of Kerry’s staff during the interim period, ruled out running for public office in the future.

“This is going to be a very short political career,” he joked.

The governor had promised his selection would be a person who had no intention of being a candidate in the special election, but he otherwise had given little detail about his deliberations.

The only possible candidate Patrick confirmed speaking with was former Rep. Barney Frank, and then only after Frank told reporters he’d spoken with Patrick. Michael Dukakis, the former governor and 1988 Democratic presidential nominee, and Victoria Kennedy, widow of U.S. Sen. Edward Kennedy, had also been mentioned as possible candidates for the interim post.

Cowan’s appointment also signals the official start of the special election race. The winner will serve out the remainder of Kerry’s term and would face another election in November 2014.

So far the only announced candidate is Democratic U.S. Rep. Edward Markey, of Malden. Fellow Democratic Congressman Stephen Lynch, of Boston, also is weighing a run and is expected to formally announce his candidacy on Thursday.
Republican officials close to Scott Brown said Tuesday that the former senator is “leaning strongly” toward running and could make an announcement early next week. The officials spoke to The Associated Press on the condition of anonymity because they were not authorized to share internal discussions.

Brown, who is still popular in Massachusetts despite his unsuccessful re-election campaign last year, would be considered a front-runner with a campaign effort that could easily be revived and an ability to raise tens of millions of dollars.

Brown also has some hurdles, including his loss last year to Democratic U.S. Sen. Elizabeth Warren.

The candidates face a tight schedule to raise money and convince voters to put them in the Senate. The Democratic and Republican primary elections are scheduled for April 30.

Massachusetts Secretary of State William Galvin said he’s ready to immediately release nomination papers. Candidates will have four weeks to collect the 10,000 signatures they need to get on the ballot.

Markey has already publicly challenged all Democratic and Republican candidates who might jump into the special election to agree to keep outside groups from spending money on political ads. He said he wants a deal similar to the so-called “people’s pledge” agreed to by Brown and Warren in last year’s Senate race.

Kerry was confirmed by the Senate on Tuesday, by a 94-3 vote, to succeed Hillary Rodham Clinton as secretary of state. His resignation takes effect Friday at 4 p.m.
Warren, who will become the state’s senior senator following Kerry’s departure despite having been in the Senate for only weeks, released a statement on Wednesday praising Cowan’s selection and promising to work closely with him in the months ahead.
Associated Press writers Steve Peoples and Steve LeBlanc contributed to this report.