WASHINGTON — With the Supreme Court confirmation hearing of Neil M. Gorsuch less than two weeks away, liberal activists are alarmed not only at the prospect of his lifetime appointment to the court, but at what they see as muted opposition from Senate Democrats.

“We are not hearing from them the intensity that we are hearing from the grass roots,” said Ilyse Hogue, president of Naral Pro-Choice America, the organizer of a recent letter from 11 progressive groups urging Democrats to step it up. “The grass roots really understands this is a do-or-die nomination.”

The tough criticism from the left underscores the Democrats’ difficult position. They need to keep their agitated and highly motivated base satisfied while not appearing to dismiss Judge Gorsuch, who has impressed members of both parties during private meetings, strictly out of political spite for the way Republicans stonewalled President Barack Obama’s nomination of Merrick B. Garland.