Bikers outraged at the thought of President Trump being impeached have decided against staging a protest ride in his defense, saying they can't persuade House Democrats not to move forward. But they say they're ready to confront Republicans if they turn against Trump during a Senate trial.

Many biker leaders who relate to Trump's bluntness and contempt for the political establishment expressed interest this year in dispatching thousands of their legions to swarm Capitol Hill in a bid to pressure Democrats to back off impeachment. But the call to ride never came.

Trump’s impeachment “is going to happen if we ride or not,” said Bikers for Trump national coordinator Dale Herndon. “The Democrats are going to vote no matter what anyone does. Even President Trump agreed with that ... This is a witch hunt, and we all know it, so why try to publicize it for the Democrats?"

Herndon said, however, "We will ride, if and when the president looks as if he is in danger with some senators flipping," specifically centrists that he calls Republicans In Name Only, or RINOs.

The group has a sign-up page for a potential ride, promoted on a Facebook group with more than 300,000 members. "We are getting up support just in case," Herndon said.

Democrats are set to impeach Trump this week. A trial in the Republican-held Senate is expected to begin in January, with at least 20 GOP votes needed to convict Trump and remove him from office. Few, if any, Republicans are expected to vote to convict.

The idea of an anti-impeachment ride emerged from Rolling Thunder co-founder Artie Muller, 74, and garnered interest in September after House Speaker Nancy Pelosi agreed to allow impeachment proceedings in response to Trump pushing Ukraine to investigate Democrats.

Muller, a former Army sergeant who served in Vietnam, denounced Pelosi as an “arrogant little bitch,” saying: “Same with Hillary Clinton. Hillary Clinton and Nancy Pelosi should open up their closets and put some charges against them.”

The idea of a ride horrified Democrats. Richard Painter, a former White House ethics lawyer to George W. Bush-turned-unsuccessful Senate candidate, wrote on Twitter, “Swastikas, racist tattoos and all — they are coming to do their leader’s bidding.”

Francis “Mac” MacDonald, a Virginia chapter leader of Rolling Thunder, said he heard no recent talk of a ride as a House vote nears. “None whatsoever,” he wrote in an email. MacDonald had said he and most of his chapter likely would have joined a ride.

In addition to the annual Rolling Thunder gatherings of veterans in Washington (ending after this year), there have been sporadic biker protests, most notably a large 2013 ride on 9/11 intended to redirect attention from an event originally billed as the Million Muslim March.

At least two leaders of the 2013 ride have discussed an anti-impeachment demonstration but have been tied down by illness and personal obligations. Democrats “won't succeed in anything other than making asses out of themselves," said one of the organizers, who said an eventual pro-Trump rally may happen.

The biker community is prone to factionalism, and leaders often find themselves denounced by rivals or men with whom they have feuded. During Trump’s 2017 inauguration, organizers who disliked each other held three separate rallies. This dynamic can allow other organizers to generate attention.

Ski Bischof, a Pennsylvanian who organized a biker rally in Washington’s Dupont Circle for Trump’s inauguration, was among the leaders interested in an anti-impeachment ride if one was called. He said, however, "I will not deal with anything that has to do with Bikers for Trump" due to his distrust of the group's leader before Herndon.

Herndon said much remains uncertain about the course of a Senate trial, including whether Republicans will seek to force testimony from Hunter Biden, the son of Joe Biden whose work for a Ukrainian energy company Trump wanted investigated, and House Intelligence Committee Chairman Adam Schiff, whom Republicans accuse of orchestrating a whistleblower complaint that triggered the impeachment proceedings.

If Republicans call witnesses, "It is going to be so good that we will all want to stay home and watch it on TV with our popcorn and beer," Herndon said.

[Opinion: Rolling Thunder rides off into the sunset]