Former Vice President Mike Pence expanded Sunday on what he sees as "profound differences" between himself and former President Trump, the presumptive GOP nominee, after announcing he would not endorse Trump in this year's election.

Driving the news: Pence said Trump is "walking away" from "keeping faith with the Constitution" on Jan. 6 and went on to list other policy differences he has with the former president.

What he's saying: "I said it during my presidential campaign — the president and I have profound differences. Many people think it's just over January 6th and, frankly, the fact that the president continues to insist that I had the right to overturn the election that day is a fundamental difference," Pence said Sunday on CBS' "Face the Nation."

• "But, I want to be clear that I've forgiven the president in my heart for what happened that day," Pence said.
• Pence listed Trump's "walking away" from "a commitment to fiscal responsibility, a commitment to the sanctity of life [and] a commitment to American leadership in the world" as other reasons he wouldn't endorse the former president.

Catch up quick: Pence said his decision not to back Trump "should come as no surprise," per an interview Friday on FOX News Channel's "The Story with Martha MacCallum."

• Pence said he preferred to keep his vote private, though he specified that he would "never vote for Joe Biden," who recently became the presumptive Democratic nominee.

Zoom out: Pence, who served under Trump as vice president for four years, has been vocal in his criticism of the former president following the Jan. 6 Capitol riot.

• He ended his own presidential bid last October amid a crowded Republican primary.

Go deeper: Pence says he won't endorse Trump