New Hampshire Republican Sen. Judd Gregg, a key participant in Saturday's late-night bailout negotiations, said Sunday afternoon that both presidential candidates played a part in the deal that was reached and that final congressional votes are likely Monday.

Gregg, the ranking Republican on the Senate Budget Committee, also said negotiators Saturday night were told in no uncertain terms from leading economists that a meltdown on Wall Street was imminent if the Bush administration's $700 billion plan was not approved as soon as possible.

"Getting this done soon, promptly, is absolutely critical to the confidence of the markets," Gregg said. "I can't understate that issue."

Both Democratic presidential nominee Barack ObamaBarack ObamaOvernight Cybersecurity: Trump tweetstorm on Russia probe | White House reportedly pushing to weaken sanctions bill | Podesta to testify before House Intel OPINION: Trump’s bluff: Perfectly legal Overnight Regulation: Senate Banking panel huddles with regulators on bank relief | FCC proposes 2M fine on robocaller | Yellowstone grizzly loses endangered protection MORE and GOP nominee John McCainJohn McCainCoats: Trump seemed obsessed with Russia probe The Hill's Whip List: Senate ObamaCare repeal bill Meghan McCain slams 'felon' Dinesh D'Souza over tweets mocking father's captivity MORE were in close contact with the lead negotiators throughout the nine-hour session Saturday afternoon and evening, Gregg said, and he confirmed media reports that economists' perspectives were sought as well.

On other key points, Gregg said: