US Vice President Kamala Harris visited Tennessee on Friday where she met with two Black lawmakers who were expelled from the state legislature on Thursday.

Justin Jones and Justin Pearson were expelled in retaliation for their protest calling for stronger gun control in the wake of a school shooting in Nashville.

A motion to oust their white colleague Gloria Johnson, who also protested, failed by one vote.

"They understood the importance, these three, of standing to say the people will not be silenced," Harris said in remarks at Fisk University, a historically Black institution.

Harris called for background checks, red flag laws and restrictions on assault rifles, and urged Republicans to "have the courage to act instead of the cowardice to not allow debate and to not allow a discussion on the merits of what is at stake."

Harris also met with other "state legislators, young people and advocates who in the wake of horrendous violence and tragedy demanded their legislators take meaningful action to address gun violence," the White House said.

How can lawmakers expel other elected lawmakers?

The expulsion of Jones and Pearson from the Tennessee House of Representatives led to outcry in the state and across the country.

It was possible firstly because of the Republican domination of the chamber; a two-thirds majority was needed for the motion to pass. Secondly, the motion's proponents argued that Jones, Pearson and Johnson — now known as "the Tennessee three" — had broken decorum rules by joining protests on the floor of the legislature.

Using this mechanism, and having the political power to get it across the line, has been extremely rare. Only two state lawmakers had previously been expelled since the US Civil War.

Jesse Chism, vice chair of the Tennessee Black Caucus, said the decision to expel two Black lawmakers for protesting "looked like a Jim Crow-era trial."

Tennessee Representative Yusuf Hakeem, a Democrat, told MSNBC that Harris' visit "lets us know firsthand that the White House is very interested and concerned in a meaningful way."

Biden invites 'Tennessee three' to Washington

US President Joe Biden also spoke with Jones, Pearson and Johnson on Friday.

He thanked them "for their leadership in seeking to ban assault weapons and standing up for our democratic values" and invited them to the White House in the near future.

A day earlier, Biden had said on Twitter that the expulsion of Jones and Pearson was "shocking, undemocratic, and without precedent."