Partisan polarization has been a fixture of American politics for several decades now.  Recently, analysts have argued its asymmetric. To be sure, Democrats have moved to the left. But they have not drifted from the middle ground as much as Republicans have to the right.   

Political scientists offer several explanations. Republican lawmakers tend to exaggerate the conservatism of their constituents. The decline of the labor movement and candidates’ hunger for campaign funds have weakened the influence of working-class progressives. Some data tell a similar story. The widely used NOMINATE technique that gives each member of Congress an ideology score reports Democrats were routinely further away from the midpoint of the scale than Republicans in the 1960s and 1970s. Since the mid-1980s, it has been the other way around, with Republicans appearing more ideologically extreme.   

Yet an analysis of the Democratic presidential field and the candidates’ policy positions and rhetoric suggests the party is moving rapidly to the left. The shift is illustrated most vividly by the U.S. senators in the race. Several are undergoing ideological transformations. As mayor of struggling Newark, New Jersey, Cory Booker encouraged private investment and doubled the number of children attending charter schools. Once elected to the Senate in 2013, he worked with Republicans Rand Paul and Tim Scott on issues like criminal justice reform. But with a presidential run in his sights, he veered leftward. He now supports debt-free college, the Green New Deal, and a single-payer government-run health system.       

Kamala Harris, the junior senator from California, has shown a conservative temperament  a major reason why many Republicans fear her. She was a tough district attorney and took a practical approach to many of her state’s biggest challenges as its attorney general. Since she has arrived in Washington, however, Harris says she wants to abolish ICE and is all in on single-payer and slavery reparations.     

Even Elizabeth Warren from Massachusetts has undergone an ideological makeover. She is continually ranked the most liberal senator by the NOMINATE scores, and Republicans have warned she is a threat to American capitalism since her first successful Senate campaign in 2012. But Warren was a Republican up until the mid-1990s, and her academic background is in the technicalities of bankruptcy law. Now she’s more inclined to overhaul than modify. She has criticized the Obama legacy. She proposes a punitive wealth tax, a comprehensive fracking ban, and breaking up large banks. As an intellectual heavyweight, her ideas are likely to shape any Democratic administration, even if shes not the head of it. 

The transformation of New York Senator Kirsten Gillibrand was particularly dramatic.  You can see why former staffers called her campaign “performative and obnoxious. As a congresswoman from upstate New York, she supported a robust border, joined the fiscally conservative Blue Dog caucus and received a perfect score for her votes from the NRA. She then ran a campaign in the feminist lane, focusing almost exclusively on a Me Too  she was instrumental in forcing Al Franken out of the Senate  and Equal Rights Amendment agenda.  Perhaps Democrats saw through her.  She’s out. 

Only three of the Democratic senators running for president have not turned appreciably leftward. Amy Klobuchar was supposed to be the moderates’ great hope. From the purple state of Minnesota, she has been a pragmatic Senator working regularly across the aisle with Republicans. According to the ideology scores I referenced above, she was the 34th most liberal Democrat in the last Congress. She has stood her ground on matters like health care and on foreign affairs, but she’s going nowhere. 

Moderate Michael Bennet from Colorado, talented although he is, has also had a hard time gaining traction by sticking to his record. He is against single-payer health care, reducing military spending, and decriminalizing currently illegal entry into the United States. He is at about 1% in the polls. 

The reliable democratic socialist Bernie Sanders hasnt turned to the left, either. He was always there and is in fact seeing the party  one he has never been a formal member of  come to him. He was the first to promote the positions his rivals have adopted. Its notable that he joins Harris and Warren  and, of course, former Vice President Joe Biden  in the top tier of candidates. 

Would the senators pursue these policies as president? For most, perhaps all, we will never know. But the conversation and candidate pledges suggest those Democrats thinking seriously about the presidential nomination and congressional leadership in the post-Obama age must be devoted progressives with socialist leanings. Any argument about the asymmetric and rightward nature of partisan polarization in American politics is about to be put to rest. 

 Andy Taylor is a professor of political science at the School of International and Public Affairs at N.C. State University. He does not speak for the university.