In what Justice Democrats celebrated as "an incredibly important moment," 2020 Democratic presidential primary candidate Sen. Elizabeth Warren on Monday endorsed Jessica Cisneros and Marie Newman—a pair of progressive primary challengers to conservative incumbent Democrats in Congress.

Cisneros, who is challenging Rep. Henry Cuellar (D-Texas), and Marie Newman, who is challenging Rep. Daniel Lipinski (D-Ill.), are both backed by Justice Democrats, which supported first-term Rep. Alexandria Ocasio-Cortez (D-N.Y.) in 2018, when she ousted a longtime congressman and leader in the Democratic Party, Joe Crowley.

"We are so proud that Jessica Cisneros and Marie Newman are being endorsed by Senator Warren, a strong fighter for working families," Alexandra Rojas, executive director of Justice Democrats, said in a statement Monday.

Rojas contrasted the Massachusetts Democrat's fresh endorsements with the positions of the Democratic Congressional Campaign Committee (DCCC), the party's official campaign arm for the House, which has tried to stifle progressive challengers trying to unseat more right-wing incumbents.

"At a time when the DCCC is rallying around pro-NRA and anti-choice Democrats like Cuellar and Lipinski," Rojas said, "it's a breath of fresh air to have candidates for president who remember what the Democratic Party should stand for."

Warren endorsing against a sitting House Democrat. Does that mean the DCCC will blacklist her? How does that work? https://t.co/LO0XXhppWy — Ryan Grim (@ryangrim) September 9, 2019

In her endorsements Monday, Warren praised the candidates' progressive positions. Of 26-year old Cisneros, the senator and presidential hopeful said:

The people of Texas' 28th district are ready for systematic change and deserve a Democrat that will be on the side of working people; not the side of big money and obstructionist Republicans... I believe Jessica Cisneros is that fighter. As an immigration lawyer and daughter of small business owners growing up on the border, Jessica knows our diversity is our strength and that when progressives are unapologetic about our values and who we're in this battle for, we win. It's time Texans had a champion in Congress who does just that. I'm proud to support Jessica.

Welcoming Warren's support, Cisneros said, "I'm so proud to receive this endorsement from Senator Warren, who has dedicated her career to fixing our corrupt political system and fighting for working families like mine."

"Our district deserves to be represented by a true Democrat who will work in Washington to improve the lives of her constituents, not corporate donors," Cisneros added. "Senator Warren's support demonstrates that we're building the momentum we need to bring real change to South Texas."

.@ewarren knows we're fighting for social & economic justice in TX and across the country -- her support proves we have the momentum to bring true representation to TX-28 next year. Help us catch up our corporate-backed opponent by chipping in today: https://t.co/ZvqMjMcZoa — Jessica Cisneros for Congress (@JCisnerosTX) September 9, 2019

Newman's 2020 primary challenge to Lipinski came after she narrowly lost to the anti-choice congressman in the last cycle. Endorsing Newman Monday, Warren said:

At a time when women's reproductive rights are under attack daily from Republican lawmakers across America, Illinoisans deserve a leader with an unwavering commitment to fighting for women's access to reproductive healthcare... Marie Newman is that leader. She understands that this isn't a moment to back down—it's time to fight back. Marie will be a champion for working families and women across Illinois' Third District, making sure their voices are heard in Washington. Marie knows that when women fight, women win. That's why I'm proud to support Marie.

Newman said Monday that "our movement in Illinois' Third District is about making life more affordable for everyone so I am absolutely thrilled to receive the endorsement of Senator Elizabeth Warren who has dedicated her career to fighting for workers and working families."

"The status quo isn't working," added Newman. "We need a real leader in Illinois' Third District, and in the White House, who will put workers, our climate, and the health of our people ahead of everything else."