Elizabeth Warren endorsed two left-wing primary challengers to House Democrats. It could be a risky play to win Alexandria Ocasio-Cortez's endorsement.

• Sen. Elizabeth Warren on Monday endorsed two progressive primary challengers to sitting House Democrats.
• The challengers - both women - are running against two of the most conservative Democrats in the House and are both endorsed by Justice Democrats, the group that backed Rep. Alexandria Ocasio's 2018 bid. 
• Warren's move could be seen as a play for Ocasio-Cortez's endorsement. 
• But the decision to undermine two long-serving Democrats carries risk. Warren could alienate the Democratic establishment and more centrist voters. 
• Recently, the Democratic party cracked down on primary challengers.
• The Democratic Congressional Campaign Committee, the party's campaign arm, announced it will no longer work with political strategists and vendors that support candidates running against sitting Democrats.
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Sen. Elizabeth Warren on Monday endorsed two progressive primary challengers to sitting House Democrats - an unusual and controversial move that could be a play to win the endorsement of star freshman Rep. Alexandria Ocasio-Cortez of New York.

The two candidates Warren endorsed - both women - are challenging Rep. Dan Lipinski of Illinois and Rep. Henry Cuellar of Texas. The veteran incumbents are among the most conservative in the House.

Both Lipinski and Cuellar are anti-abortion and voted against marriage equality. While Lipinski opposed Obamacare, Cuellar has an A rating from the NRA. The two congressmen represent deep blue districts that Republicans have no shot of flipping. 

"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," Warren said in a statement in which she endorsed Jessica Cisneros' bid against Cuellar. 

Ocasio-Cortez backers praise Warren

Both Cisneros, a 26-year-old human rights and immigration lawyer, and Lipinski's challenger, Marie Newman, are endorsed by Justice Democrats - the progressive group that powered Ocasio-Cortez's insurgent primary campaign in 2018. The group praised Warren's move as "a breath of fresh air."

Read more: Alexandria Ocasio-Cortez got 2020 Democrats talking about climate change, but their plans to address it diverge wildly

Warren went on, "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."

Newman, a former marketing executive, is challenging Lipinski for the second time after coming within two points of being him in 2018. 

"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," Warren said in a Monday statement. "Marie Newman is that leader." 

Warren is likely gunning for Ocasio-Cortez's eventual endorsement. And the 29-year-old lawmaker is pushing for more primary challengers in her mold in 2020, and has voiced support for both Warren and Sen. Bernie Sanders as presidential candidates. 

The Massachusetts Senator might also be factoring in her strong poll numbers. An NPR/PBS NewsHour/Marist poll this week found that she's the most popular 2020 candidate among Democratic and Democratic-leaning voters, with 75% favorability. 

Read more: The Democratic Party is cracking down on candidates who hope to be the next Alexandria Ocasio-Cortez, and progressives are fighting back

A risky and controversial move

Warren's decision to undermine two long-serving members of her own party could rub some Democrats the wrong way.

She isn't the only presidential candidate to wade into primaries this year. Sens. Sanders and Kirsten Gillibrand and Washington Gov. Jay Inslee also endorsed Newman earlier this year. But it is extremely rare for Democrats - particularly prominent and mainstream figures - to help unseat colleagues in their own party. 

But the endorsements mark a break for Warren, who's stayed away from Democratic primaries in the past. She didn't endorse either Hillary Clinton or Sanders in the 2016 presidential primary. Warren also declined to back progressive House challengers in 2018, including Rep. Ayanna Pressley, who went on to defeat a Democratic incumbent in Warren's home state of Massachusetts. 

And the Democratic party has in recent months cracked down on primary challengers - even in safe districts. 

In late March, the Democratic Congressional Campaign Committee, the party's campaign arm, announced it will no longer work with political strategists and vendors that support candidates running against sitting Democrats.

The move - which many say simply formalized an unofficial practice - was met with fierce opposition largely from progressives, who say it will hurt first-time candidates, particularly women and people of color.

Ocasio-Cortez called the DCCC's policy "extremely divisive" and urged her supporters to "pause" their donations to the group.

By endorsing these two House challengers, Warren's indicating she's on Ocasio-Cortez's side.