Mary Glassman, the former first selectman of Simsbury and two-time Democratic candidate for lieutenant governor, was the first Monday to declare her candidacy for Congress in the wake of the decision by U.S. Rep. Elizabeth Esty, D-5th District, not to seek re-election. Glassman is unlikely to be the last to enter the race for a suddenly open seat. 

“I’ve given it a lot of thought, and I’m in,” Glassman said.

Glassman was among the Democrats who acknowledged starting to think about the race over the weekend, as Esty, a three-term Democrat who had been strolling to re-election, struggled to cope with fallout from the disclosure that she waited three months in 2016 to dismiss a chief of staff accused by another employee of physical and emotional abuse.

Esty’s announcement was a blow to Republicans, who would have preferred a run against a damaged incumbent over an open race in a district last won by a Republican in 2004, said Dan Carter, the GOP’s U.S. Senate nominee in 2016 and a possible 5th District candidate.

“The fact she is not running doesn’t necessarily deter me, because I think I’d be a good candidate,” Carter said. But he also acknowledged, “There is no doubt in my mind that a wounded Elizabeth Esty would have been easier to beat.”

The 5th District covers roughly the western third of Connecticut, running from the Massachusetts line along the New York border to Danbury. It includes small towns in the Litchfield Hills, the older mid-sized cities of Waterbury, Danbury, Meriden and New Britain, and the well-to-do Farmington Valley suburbs of Avon, Farmington and Simsbury.

Republicans carried the 5th District in the 2014 race for governor. Esty won the open seat in 2012, succeeding Democrat Chris Murphy, who was elected to the U.S. Senate. Murphy had unseated Nancy Johnson, a long-time GOP incumbent, in 2006.

Manny Santos, the former mayor of Meriden, opened a campaign weeks ago for the GOP nomination.

J.R. Romano, the Republican state chairman, said Monday night he was unsure who else might now be attracted to run. New Britain Mayor Erin Stewart told him she will remain in the race for governor and is not considering a congressional campaign, he said.

Some Republicans speculated that state Rep. William A. Petit, R-Southington, might run, but he said through a spokesman Monday night he was disinclined.

Rep. Michelle Cook, D-Torrington, said she was weighing a run, making calls to explore the feasibility of entering what will be an unusual sprint of a campaign: The nominating conventions are next month.

“At this point, it’s been a 24-hour whirlwind of conversations,” Cook said.

Former state Sen. Dante Bartolomeo, D-Meriden, said she was flattered to be approached as a potential candidate, but she is not going to run. Rep. Liz Linehan, a Democrat who lives in Esty’s hometown of Cheshire, said the same. Her phone has been ringing since Thursday, she said, “but I’m not interested.”

Instead, she issued a statement saying Esty was doing the right thing by not running for re-election. “Her failure to take decisive action to protect her staff from harassment and abuse cannot be ignored,” Linehan said. “If we are going to confront the epidemic of sexual harassment in the workplace, no one can be immune to accountability.”

Glassman twice was recruited to run for lieutenant governor. In 2006, she ran with Dannel P. Malloy; She won her primary, while Malloy lost the gubernatorial nomination to New Haven Mayor John DeStefano. In 2010, she was Ned Lamont’s running mate. Lamont and Glassman lost the Democratic primary to Malloy and Lt. Gov. Nancy Wyman.

Gassman had two eight-year tenures as first selectman of Simsbury, separated by a break of eight years. She won her first term in 1991, an upset victory for a Democrat in a Republican suburb.

Glassman said Esty’s fall saddened her.

“Any time a public servant disappoints you, it’s a sad day,” Glassman said. “She’s been a good representative.”