Harvard Law professor Alan Dershowitz said Friday he'll leave the Democratic Party if Rep. Keith Ellison (D-Minn.) is appointed the next chair of the Democratic National Committee (DNC).

“I’m going to tell you right here on this show, and this is news – if they appoint Keith Ellison to be chairman of the Democratic Party, I will resign my membership to the Democratic Party after 50 years of being a loyal Democrat,” Dershowitz told the Fox Business Network.

Dershowitz criticized Secretary of State John KerryJohn Forbes KerryFeehery: Oprah Dem presidential bid unlikely Dem hopefuls flock to Iowa Change in Iran will only come from its people — not the United States MORE for his tough position on Israel and predicted that the appointment of Ellison will make others leave the Democratic Party.

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"If they now appoint Keith Ellison, who worked with [Nation of Islam leader Louis] Farrakhan, to be chairman of the DNC, you’re going to see a lot of people leave,” he said.

Ellison has been vocal about his support for Israel after CNN reported recently on comments he made several years ago defending the Nation of Islam leader.

Dershowitz also knocked the Obama administration after the passage of a U.N. Security Council resolution last week condemning Israeli settlements. The resolution passed 14-0 as the U.S. abstained.

"I will not be a member of a party that represents itself through a chairman like Keith Ellison and through policies like that espoused by John Kerry and Barack ObamaBarack Hussein ObamaMcCarthy: ‘No deadline on DACA’ Democrats will need to explain if they shut government down over illegal immigration Trump’s first year in office was the year of the woman MORE," Dershowitz said.

Kerry said this week that Israel's settlement policy poses a threat to regional peace talks with the Palestinians.

"If the choice is one state, Israel can either be Jewish or democratic,” Kerry said during a speech earlier this week. “It cannot be both, and it won't ever really be at peace."

Israeli Prime Minister Benjamin Netanyahu criticized Kerry’s speech on Wednesday, calling it a “great disappointment” that undermined the Jewish state.