Quinnipiac University's latest national poll has found that Sen. Kamala Harris and at least four other Democratic presidential nominees are ahead of Trump.

According to the new poll, former Vice President Joe Biden has a 54% to 38% lead over Trump in a head-to-head matchup in Michigan, a state Trump narrowly won in 2016. He maintains the most significant margin compared to the other Democratic presidential candidates.

Sen. Bernie Sanders, Elizabeth Warren and Kamala Harris are also all leading Trump in the poll.

"In hypothetical matchups between President Trump and the top five Democratic presidential candidates, one key number is 40," said Quinnipiac University Polling Analyst Mary Snow. 

"It's the ceiling of support for Trump, no matter the candidate. It hovers close to his job approval rating, which has stayed in a tight range since being elected."

The downward spiral in the economy and the recent trade war with China may be the main factor when it comes to the president's decline in popularity.

According to the new poll, for the first time since Trump was elected, more voters say that the national economy is getting worse than getting better, with 37 percent saying it is getting worse, 31 percent saying it is getting better, and 30 percent saying it is staying the same. 

This compares to a June 11, 2019 poll in which 23 percent of voters said that the national economy is getting worse, 39 percent said it is getting better, and 37 percent said it is staying the same.