South Carolina mayor says conventional wisdom will be tested in 2020 Dem primaries

Conventional wisdom will be put to the test in the 2020 Democratic primaries, according to Columbia, S.C., Mayor Stephen Benjamin (D).

"I think all bets are off the table in [that] no one who's smart will take anything for granted," Benjamin told Hill.TV's Jamal Simmons on "Rising."

"They'll come and spend the time learning the state, talking to them about what's important," he added in a Tuesday interview that aired the following day.

"I think some of the conventional wisdom will be tested this time," he said, referring to the primary season as a whole.

South Carolina's will be the third primary contest in 2020, after the Iowa caucuses and the New Hampshire primary.

"Everyone is going to have to come and grind it out," he said. "Julián Castro was a fantastic HUD [Housing and Urban Development] secretary. He was very good, I will tell you, to the people of Columbia during his tenure in the Obama administration." 

Castro launched his White House bid earlier this month.

Benjamin also praised other candidates and potential contenders, including Sens. Kirsten GillibrandKirsten GillibrandNow is the time for a US data protection agency The Hill's Campaign Report: Warren up, Bloomberg down after brutal debate Ginsburg, accepting lifetime achievement award, urges working fathers to take an active role in kids' lives MORE (D-N.Y.) and Elizabeth WarrenElizabeth Ann WarrenJack Black endorses Elizabeth Warren Democrats view Sanders as having best shot to defeat Trump: poll Poll: Biden, Sanders tied in Texas, followed by Warren MORE (D-Mass.), former Vice President Joe BidenJoe BidenBiden faces do-or-die primary in South Carolina Democrats view Sanders as having best shot to defeat Trump: poll Karl Rove: 'Long way to go' for Sanders to capture nomination: 'The field is splintered' MORE and former New York City Mayor Michael Bloomberg.

The field of presidential hopefuls is expected to grow in the coming weeks. 

A Harvard CAPS/Harris Poll survey released exclusively to The Hill on Tuesday found that 43 percent of respondents said they would cast their vote for a Democratic candidate in 2020.

— Julia Manchester