Political tribalism started in the 1990s, says NBC News political reporter

NBC News political correspondent Steve Kornacki said in an interview that aired Tuesday on "Rising" that political tribalism in the U.S. was fueled during the 1990s. 

"What a lot of people don't remember when they think back at it was how politically tumultuous it was," Kornacki told Hill.TV's Krystal Ball last week, citing the partisan rivalry between former President Clinton and former Speaker Newt Gingrich (R-Ga.)  

"All of the wars and the conflicts, and the characters, and the divisions, to me in that decade they build and they build to that moment, Nov. 7, 2000, the presidential election. It's basically the closest thing this country will ever see to a perfect tie," he continued, referring to President George W. Bush's victory over Al GoreAlbert (Al) Arnold GoreAnother VPOTUS tries for POTUS: What does history tell us? Several factors have hindered 'next up' presidential candidates in recent years Montana Gov. Bullock enters presidential race MORE

"The map that emerges from that election, the red-blue map, that's the first time we ever really start talking about red states and blue states, the red America and blue America, the way we do today. Those colors literally had no meaning politically, no meaning for political parties before election night 2000," he said. 

Kornacki's comments come as Republican and Democratic candidates look to appeal to their bases and sway undecided and independent voters ahead of November's midterm elections. 

The contests are widely expected to be a referendum on President TrumpDonald John TrumpTrump rips Dems' demands, impeachment talk: 'Witch Hunt continues!' Nevada Senate passes bill that would give Electoral College votes to winner of national popular vote The Hill's Morning Report - Pelosi remains firm despite new impeachment push MORE's first two years in office. 

Kornacki is promoting his new book, "The Red and the Blue: The 1990s and the Birth of Political Tribalism."

— Julia Manchester