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Half of registered U.S. voters disapprove of President Trump's performance as president, versus 42 percent who approve, according to a new Politico/Morning Consult poll. Those are Trump's worst numbers in that poll. The new poll was conducted Friday through Sunday, after Trump fired FBI Director James Comey but before bombshell reports on Monday and Tuesday about Trump passing classified information to the Russians and asking Comey to drop an investigation of Trump aide and National Security Adviser Michael Flynn. In the previous poll, taken Tuesday through Thursday, 46 percent approved and 47 percent disapproved of Trump's performance.

There is a partisan split in the new poll: 79 percent of Republican voters approve of Trump's job while 79 percent of Democrats and 50 percent of independents disapprove. Overall, 38 percent of respondents "strongly disapprove" of Trump versus 19 percent who "strongly approve." "President Trump's approval has fallen from 51 percent in mid-April to 42 percent today," said Morning Consult chief research officer Kyle Dropp. "A less reported-on trend is the waning enthusiasm for Trump in his base. When Trump took office, 56 percent of his voters strongly approved of his job performance. Today that number stands at 42 percent." The poll, of 2,001 registered voters, has a margin of error of 2 percentage points.

The weekly Politico/Morning Consult survey "has tended to show more positive results for Trump than most other public polls," Politico notes. The RealClearPolitics average has Trump at 40 percent approval, 55 percent disapproval, just a notch better than the FiveThirtyEight average:

FiveThirtyEight's Nate Silver says it is unrealistic to expect Trump's base to abandon him quickly, but adds that "so far, Trump has lost about 1 point off his approval rating per month," which "could add up to a big problem" after a few months.