NEW YORK — Susan Rice, who served as national security adviser under President Obama, won’t be challenging Republican Sen. Susan Collins of Maine in 2020.

Rice told former Obama administration official Alyssa Mastromonaco at the 10th annual Women in the World Summit on Thursday in New York that she loves Maine and that her family has deep roots in the state. But she said she decided with her family “that the timing really isn’t right for us.”

Rice tantalized Democrats in October when she expressed interest in Collins’ seat during the contentious confirmation hearing for Supreme Court Justice Brett Kavanaugh. She said at the time that Collins “betrayed women across this country” by supporting Kavanaugh.

Rice said during the event on Thursday that her daughter is going into her junior year of high school and that her family has already sacrificed for her.

“I’ve given this a lot of thought, and in the course of weighing it all, I’ve decided with my family that the timing really isn’t right for us,” she said.

Her announcement could free other Democrats to enter the race.

So far, no high-profile Democrat has announced a challenge to Collins next year. But the race is still early, and Collins herself hasn’t formally announced she’ll seek re-election.

Sen. Susan Collins, R-Maine Associated Press/J. Scott Applewhite

Collins’ office had no immediate comment Thursday.

Collins is a self-described centrist in an era of increasingly polarized politics. First elected to the Senate in 1996, she’s now the last Republican member of Congress from New England.

Rice’s maternal grandparents emigrated from Jamaica to Maine in the 1910s. Her grandfather, David Augustus Dickson, worked as a shipper, porter and janitor. Rice’s grandmother, Mary Dickson, a maid and seamstress, was named Maine State Mother of the Year in 1950.