Peterson was one of two Democrats to sign onto the amicus brief.

Rep. Collin Peterson of Minnesota has once again defied party lines, this time in an abortion rights brief.

An amicus brief signed by 39 senators and 168 representatives Thursday urged the Supreme Court to consider taking up Roe v. Wade. Of those signing the brief, only two were Democrats: Peterson and Rep. Daniel Lipinski of Illinois.

A number of notable Republican members of Congress up for reelection did not sign the brief, including Senate Majority Leader Mitch McConnell.

The brief relates to the June Medical Services, LLC vs. Gee case, which would determine whether a Louisiana restriction requiring doctors providing abortion services to have admitting privileges at a local hospital. The members of Congress who signed the brief argue that this requirement is not meant to inhibit abortion services but act as a safety measure.

An opposing brief signed by 197 members of Congress notes a similar law in Texas was struck down in District Court because it was found to impose undue burden on abortion access.

Minnesota Reps. Betty McCollum and Ilhan Omar, and Sens. Amy Klobuchar and Tina Smith both signed the opposing brief.

They also ask the Supreme Court to reconsider a number of cases pertaining to abortion rights in the brief. This includes Planned Parenthood v. Casey, which prohibits states from establishing standards that place "undue burden" on a woman’s right to an abortion.

Those signing onto the brief argue the ruling of Wade and other related cases have provided inconsistent opinions.

“These incessant retrenchments show that Roe has been substantially undermined by subsequent authority, a principal factor the Court considers when deciding whether to overrule precedent. Casey clearly did not settle the abortion issue, and it is time for the Court to take it up again,” the brief reads.

According to the New York Times, a decision on the case is expected in June.

This isn’t the first time Peterson has voted largely against his party. Last month, Peterson was one of only two Democrats to vote against both articles of impeachment against President Donald Trump.

He has shown himself willing to defy the Democratic party on several occasions during President Trump's tenure, with his 7th District having voted overwhelmingly for Trump during the 2016 elections.