For the first time, more Americans support impeaching President Donald Trump than oppose the idea, according to a new survey from Public Policy Polling.

The poll, conducted in the wake of Trump firing former FBI director James Comey, found 48 percent in favor of impeachment and 41 percent against. Just 43 percent of respondents think Trump is going to serve his full term as president.

"One thing hurting Trump is that Americans expect honesty from their president and his aides, and they feel like they're not getting it," the polling operation said in a statement (pdf).

Indeed, only 38 percent of voters say they consider Trump to be honest and a full 51 percent "outright say they consider Trump to be a liar." Meanwhile, despite Trump's assertion in a tweet last week that it was unreasonable to expect his surrogates to always be accurate, the vast majority of respondents to the poll (77 percent) said they do expect the president's press secretaries to tell the truth all the time compared to only 14 percent who say that isn't the expectation.

On the matter of the president's tax returns, which he said last week would stay hidden until he's out of office, the poll found Trump to be out of step with his constituents' desires. Not only do 62 percent of voters continue to think he needs to release them, compared to only 29 percent who think it's not necessary, but 61 percent "would even support a law requiring candidates for president to release 5 years of tax returns in order to appear on the ballot, with just 28 percent opposed to such a provision," Public Policy Polling reports.

The survey—conducted May 12-14 among 692 registered voters and with a margin of error of +/- 3.7 percent—almost certainly reflects negative response to Comey's firing. Despite only 24 percent of respondents seeing Comey favorably, compared to 40 percent who harbor a negative opinion, only 37 percent of voters support Trump's decision to dismiss the FBI director and the majority don't buy the administration's explanation for why Comey was canned. Fifty-four percent say the FBI's investigations into Russian involvement in the 2016 election is the reason Comey got the boot.

Pollsters did not get the chance to ask voters about Monday's revelations that Trump spilled classified intelligence during a meeting last week with Russian diplomats, but it's likely that the latest reporting could further spike support for impeachment, with a wide array of voices saying proceedings must begin.

Still, despite such chatter, the president on Tuesday characterized his meeting with Russia as "very successful"—and refused to answer further questions about the nature of the disclosure or the possible damage it may have caused.

An increasingly popular petition launched in the wake of Trump's inauguration and calling for Congress to begin an impeachment investigation had close to one million signatures as of Tuesday afternoon.