WATCH: Texas "Trump Train" Trial Begins

On a busy Texas highway just days before the 2020 election, a convoy of Donald Trump's supporters weaved close to a Biden-Harris campaign bus, endangering its passengers as well as other motorists.

While her fellow passengers called 911 for help, former Democratic lawmaker Wendy Davis recorded the vehicles on her phone. Just under four years later, a jury watched the video in a federal court in Austin on Monday.

It was the first day of a civil trial seeking to hold some of those Trump supporters responsible for what Davis, who ran for Governor in 2014,  and others on the bus say was an "intimidating threat of political violence."

“It was a day that was very different from anything I experienced campaigning,” said Davis, who testified that she felt "riddled with fear and anxiety."

In opening statements, a lawyer for Davis and the other plaintiffs argued that the six “Trump Train” drivers acted together in a pre-planned attack aimed at intimidating the campaign into canceling its remaining events in Texas.

The defense argued that the drivers "did not conspire against the Biden-Harris campaign bus" that day, and instead joined the other drivers in the "Trump Train" as if it were a pep rally.

They also claimed that the bus had several opportunities to exit the highway on its way from San Antonio to Austin.

 Videos of the confrontation on Oct. 30, 2020, including some recorded and shared on social media by the Trump supporters themselves, show a group of cars and pickup trucks — many adorned with large Trump flags — crowding the campaign bus, boxing it in, slowing it down and keeping it from exiting the highway.