WASHINGTON — As most Republicans were taking a victory lap the morning after the elections, a group of conservatives huddled anxiously in a conference room not far from Capitol Hill and agreed that now is the time for confrontation, not compromise and conciliation.

Despite Republicans’ ascension to Senate control and an expanded House majority, many conservatives from the party’s activist wing fear that congressional leaders are already being too timid with President Obama.

They do not want to hear that government shutdowns are off the table or that repealing the Affordable Care Act is impossible — two things Republican leaders have said in recent days.

“If the new Republican leadership in the Senate is only talking about what they can’t do, that’s going to be very demoralizing,” said Thomas J. Fitton, president of Judicial Watch, a conservative advocacy group that convenes a regular gathering called Groundswell. Any sense of triumph at its meeting last week was fleeting.