These were the states in which Ms. Warren was supposed to build momentum, propelled by her base of white, college-educated liberals. She was supposed to prove that she was the person who could unite the Democratic Party and demonstrate the energy behind ridding Washington of corruption.

Instead, after Mr. Buttigieg led the attacks on Ms. Warren over her health care plan that began in October, he is snaring her primary voters — including women of Ms. Warren’s generation like Ms. Bagley and Ms. Luddy — with a platitude-heavy message of uniting the country and restoring democracy…

Mr. Buttigieg has been aided by the concept of electability, which has hung over the primary season and can disadvantage women running for office in particular. Ms. Warren’s allies, who have seen her frequently faced with questions about whether a woman can win, believe Mr. Buttigieg has been treated with kid gloves by journalists who see themselves in a 38-year-old man more than a 70-year-old woman.