They waved signs and flags, marched and chanted and came together over one single cause: Removing President Donald Trump from office.

On the eve of what's expected to be a vote by the U.S. House of Representatives to impeach Trump, rallies were held in four Alabama cities as part of hundreds planned across the country calling on lawmakers to hold the president accountable.

"I spent 20 years in the Army," Lawrence Lee said as he addressed an estimated 150 people attending the pro-impeachment rally in Huntsville. "I've served my country proudly. When I raised my hand, I swore to uphold and defend the Constitution. I didn't swear to uphold the behavior of certain individuals. I didn't swear to support the people I like.

"I swore to uphold and protect the United States Constitution and that's exactly what we're doing here tonight."

Pro-impeachment rally marches around Madison County Courthouse at the end of rally in downtown Huntsville. pic.twitter.com/xxPARIUF4x — Paul Gattis (@paul_gattis) December 18, 2019

The rally has grown to 100+ people and they’re now walking around the perimeter of Linn Park. pic.twitter.com/4RKzFrIYrX — Howard Koplowitz (@HowardKoplowitz) December 17, 2019

Pro-impeachment rallies also took place in Birmingham, Mobile and Montgomery – part of a national grassroots movement organized by impeach.org. Rallies were to be held in all 50 states as well as the District of Columbia.

If the House votes to impeach Trump, he will face trial in the U.S. Senate – where he is expected to be cleared of the two articles of impeachment by the Republican-controlled upper chamber that have been brought against him by the Democrat-controlled House.

And even if the outcome seems apparent, those rallying for Trump's impeachment maintained hope that their voices could sway the Senate.

“I think everybody should always do the right thing regardless of what they think the outcome will be," said Rusty Spell of Auburn, one of about 70 people who rallied on the steps of the state capitol in Montgomery. "There’s still a chance if the American people are loud enough the Senate will listen.”

Alabama's 6 Republican representatives in the House have said they will vote against impeachment while Terri Sewell, the lone Democrat, has said she will vote for impeachment.

Linda Fisher of Prattville leads crowd in a chat at rally for impeachment of President Trump in front of Capitol in Montgomery. #alpolitics pic.twitter.com/eorMb8mIaE — Mike Cason (@MikeCasonAL) December 18, 2019

“We believe that Donald Trump is cheating in the upcoming election ... and we hold our lawmakers to keep him accountable,” said Shea Rives of Birmingham Indivisible at a Linn Park rally with about 100 people.

About 60 protestors gathered in downtown Mobile calling for Trump's impeachment – with one man carrying a sign that said, "All I want for Christmas is Trump impeached."

As the rallies took place, with chants such as "Impeach and remove," no counter-protestors were seen. One Trump supporter in Huntsville, wearing a red "Make America Great Again" cap, stood on the edge and said he just came out of curiosity.

As the protest played out, traffic slowed along West Side Square in Huntsville and one man rolled down his window, stuck his head out and yelled, "Boo!" as he drove by.

AL.com reporters Mike Cason, J.D. Crowe, Levi Edwards and Howard Koplowitz contributed to this report.