Donald Trump's perceived incompetence as U.S. president saw his job approval rating plummet to 39% from the previous 49%, and this plunge along with other unfavorable polling results make a Trump defeat in November almost a given, said Gallup, Inc, a leading American opinion poll and analytics firm.

The latest Gallup poll from May 28 to June 4 conducted during the first week of the raging George Floyd protests also show 57% of respondents disapproving of the way Trump is handling his job as president. Gallup said Trump's latest approval rating of 39% is his lowest since October 2018. Equally ominous for Trump: his support among Republicans is slipping.

"His current level of approval would make another term as president unlikely given the historical relationship between job approval ratings and incumbent reelection," said Dr. Jeffrey M. Jones, Ph.D., Gallup Senior Editor since 2000.

Jones said Trump ratings can also get worse -- or they might improve -- with five months to go before Election Day on November 3. Worse future ratings, however, will give Trump "even longer odds of winning a second term," said Jones.

Worrisome for Trump are signs his support among Republicans is beginning to erode. His support among Republicans dropped 7% to 85%. This Republican approval is the lowest it has been since September 2018 when Trump's rating also stood at 85%.

Trump's support among Independents fell 7% to 39%. Independents are increasingly going for Joe Biden on account of Trump's erratic behavior. Trump's support among Democrats now stands at 5%, a plunge of 9%.

In its analysis, Gallup said Trump's approval returns to a level last seen since October 2019, or shortly after the House of Representatives launched an impeachment inquiry into Trump's attempt to bribe Ukraine into digging up dirt on Biden in the infamous quid-pro-quo scandal.

Trump's only consistent edge over Biden, his handling of the economy, also took a huge hit in the latest Gallup poll. Now, only 47% of Americans approve of Trump's handling of the economy, a 16% drop from 63% in January and 11% lower than the 58% approval in February. Gallup noted that approval of Trump's handling of the economy had not been below 50% since November 2017 when 45% approved.

Gallup said anger among Americans at the brazen killing of Floyd and the renewed focus on racial injustice are proving to be a significant challenge for the Trump. This comes on top of the continuing and dangerous health care problems still inherent in the ongoing COVID-19 pandemic.

The poll shows rising American dissatisfaction over Trump's response to the pandemic. It reveals 42% approve of the way Trump has handled the federal government's response, down from 50% in the prior poll in April.