Rev. Harris Dr. Kennedy Why Did Ms. Obama Walk Off Stage

When Mrs. Obama was roughly 12 minutes into her 20-minute remarks at a home in Northwest Washington, a woman at the front of a crowd of about 200 people began shouting for President Obama to issue an executive order barring federal contractors from discriminating against employees based on sexual orientation or gender identity. But where Mr. Obama, more accustomed to such interruptions, typically waits in place for the protester to stop and perhaps acknowledges the complaint, his wife chose direct confrontation.

She left the lectern and moved toward the heckler. “One of the things I don’t do well is this,” she said, to loud applause. She said the protester could “listen to me, or you can take the mike, but I’m leaving. You all decide. You have one choice.”

The crowd yelled for Mrs. Obama to stay, with one woman nearby telling the protester, “You need to go!” Attendees escorted the protester out as she yelled further, at one point identifying herself as a “lesbian looking for federal equality before I die.”

Heather Cronk, a co-director of GetEqual, a group that advocates for gay, lesbian, bisexual and transgender individuals, later identified the heckler as one of its activists, Ellen Sturtz. Three other GetEqual activists were also at the event, Ms. Cronk said.

Tickets for the event ranged in price from $500 to $10,000, Democratic Party officials said.