Democratic pollster Ken O'Brien advised on Monday that the party should not be making "promises of free everything" to voters, specifically referring to New York Democratic congressional candidate Alexandria Ocasio-Cortez.

"I disagree with Alexandria Ocasio-Cortez on many points, and also on a condition of 4 percent unemployment or so, we don't need to be guaranteeing jobs," O'Brien told Hill.TV's Joe Concha on "What America's Thinking."

"There's still a lot of economic opportunity out there, and I think that's where the Democratic Party needs to focus, rather than promises of free everything," he continued.

Ocasio-Cortez, who identifies as a democratic socialist, beat longtime Rep. Joseph Crowley in the Democratic primary for New York's 14th Congressional District.

The progressive candidate has championed various liberal causes such as debt-free college and single-payer health care.

Establishment Democrats, including House Minority Leader Nancy Pelosi Nancy PelosiPelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' On The Money: Anxious Democrats push for vote on COVID-19 aid | Pelosi, Mnuchin ready to restart talks | Weekly jobless claims increase | Senate treads close to shutdown deadline Trump signs largely symbolic pre-existing conditions order amid lawsuit MORE (Calif.), have warned that Ocasio-Cortez's platform may work in her reliably liberal district, but may not be as easy to sell across the country.

— Julia Manchester