Senate Majority Leader Harry ReidHarry ReidChris Murphy’s profile rises with gun tragedies Republicans are headed for a disappointing end to their year in power Obama's HHS secretary could testify in Menendez trial MORE (D-Nev.) and Minority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellGun proposal picks up GOP support Children’s health-care bill faces new obstacles Dems see Trump as potential ally on gun reform MORE (R-Ky.) are set to take their fight on political spending to a new venue next week.

The Senate Judiciary Committee announced Saturday that the pair would appear before the panel as witnesses, as lawmakers consider a constitutional amendment that would limit the amount of cash outside groups can pump into the political system.

The two are no strangers to sparring over the issue, among many others, but their upcoming turn as congressional witnesses provides a novel way for that fight to continue.

Reid has called for a new constitutional amendment that would reverse recent Supreme Court decisions that cleared the way for unlimited spending by outside groups. The Senate’s top Democrat has been a vocal critic of the wealthy Koch brothers, bashing the GOP donors on a seemingly daily basis.

The high court used rulings like its Citizens United decision to roll back limits on how much groups can give to political campaign on free speech grounds. That has renewed Democratic efforts to put those limits back in place, arguing it gives wealthy juggernauts a disproportionate role in the political debate.

Meanwhile, McConnell has pushed back on Reid’s efforts just as much, arguing that attempts to curb political spending amounts to silencing free speech under the First Amendment.

The two will face off as witnesses, and the committee will also hear from a second panel of stakeholders and experts that same day.

Passing such an amendment is likely to be a highly partisan affair. Such a plan could clear the Democrat-controlled committee, but is very unlikely to receive the two-thirds support needed to put the amendment in place.