The last time a third-party candidate went up against Democratic and Republican candidates in a TV debate was Ross Perot in the 1992 election. Marty Lederhandler/AP The most important lawsuit you don’t know about yet is going to federal court on Thursday.

If it succeeds, voters in 2020 may be able to select a third viable candidate for president in a nationwide election called America's Independent Primary.

The winner would then go up against the Democratic and Republican nominees in a three-way contest that would give Americans real choices.

It's exactly the kind of change Americans want.

This year, to an extent unprecedented in modern elections, Americans held strongly negative views of both major-party candidates.

On Election Day, Donald Trump and Hillary Clinton each had unfavorable ratings that exceeded their favorable ratings – and President-Elect Trump still does.

Trump and Clinton were nominees of parties founded in the 19th century that have grown out of touch with voters. Surveys show that self-designated independents outnumber either Democrats or Republicans, and most voters want to be able to vote for an independent for president.

But Democrats and Republicans maintain their duopoly through institutions like the Commission on Presidential Debates (CPD), an organization whose rules have excluded independent candidates for the past 24 years.

No one can be elected president without the enormous attention that comes from being in the final fall debates, which are now locked up by the CPD.

The current CPD rules require that an independent receive at least 15% support in an average of five polls taken a few weeks before the first debate in late September of election year.

No candidate who did not compete in a Republican or Democratic primary has exceeded that level since the televised debates began in 1960 – which, apparently, is how the CPD wants it.

Level the Playing Field, et al. v. FEC, the lawsuit being heard Jan. 5 in U.S. District Court in Washington, DC, could end the two-party regime and open up US politics for years to come. The non-partisan group that filed the suit claims the CPD, whose board is filled with party stalwarts, is violating election laws in order to limit voters’ choices.

In the 1992 election, Ross Perot was polling at 8% just before the first debate on Oct. 11. He was admitted to that debate because the CPD’s rules were more lax then.

When the election took place, Perot received 19% of the vote. A few years later, the CPD, evidently responding to fears of a future interloper, instituted the 15% threshold.

Jill Stein. D. Ross Cameron/AP No one has come close since.

This fall, Gary Johnson, the Libertarian candidate, averaged 8% in the polls selected by the CPD. Jill Stein, the Green candidate, averaged 3%. The two were excluded from the debates that followed, and their actual tallies in the election fell to just 3% and 1%, respectively.

A national primary could turn out strong independent candidates and bring them media attention and financial support – but only if the CPD agrees beforehand to let the winner debate. (That agreement could be contingent, for example, on the winner receiving a minimum number of votes in the primary.)

The lawsuit would make the Federal Election Commission (FEC) force the CPD to act as a truly non-partisan, rather than bi-partisan, institution and to open the debates to a third candidate.

The CPD’s proceedings are kept secret, but it’s clear that criticism is having an effect.

Gary Johnson. Mark Kauzlarich/Reuters One-third of the commission’s board members, including former Indiana Gov. Mitch Daniels and former Defense Secretary Leon Panetta, have resigned in the past year.

Still, Americans won’t be able to choose a strong independent candidate for the debate stage unless the court comes hard down on the side of democracy in the biggest lawsuit you had never heard about.

In the absence of change, we are stuck with the nominees decided for us by the two traditional parties, and we will continue to face unpalatable, even dangerous, choices.

Stay tuned.

Dylan Ratigan, a former MSNBC and CNBC anchor and Bloomberg global managing editor, is managing partner of Helical Holdings, a solar, hydroponic and water systems design and manufacturing company.