EL PASO, Tex. — As 20 Democrats debated on national television, Senator Sherrod Brown of Ohio and his wife, the Pulitzer Prize-winning columnist Connie Schultz, texted each other a running critique of the candidates.

This was not just another politically engaged couple talking about the 2020 race.

“You can’t help but think, ‘I could have done that better,’” Mr. Brown recalled in an interview.

“This is the first time I really thought, ‘I wish you were up there,’” Ms. Schultz told her husband. She had watched the debates in June at their home in Cleveland, while Mr. Brown, who considered but passed on a 2020 run, was in Washington, where the Senate was in session.

“A number of colleagues came up to me and said that ‘I wish you would have been up there,’” Mr. Brown said.