Biden, according to the poll, remains the most electable candidate in voters' minds, with 48 percent saying he's the one to beat Trump in the 2020 general election, but Warren is gaining ground. The Massachusetts senator sits at 21 percent, an increase from 9 percent in August.

The new poll also found that voters are almost evenly divided over whether President Donald Trump should be impeached, with 46 percent saying he should be impeached and removed from office and 48 percent saying he should not be impeached.

Support for impeaching Trump has seen a slight uptick in the past week. In an Oct. 8 Quinnipiac poll, 45 percent of voters said Trump should be impeached, while 49 percent said he shouldn’t.

Two-thirds of voters surveyed in the poll believe it is unacceptable for a sitting U.S. president to ask a foreign leader to investigate a political opponent, but only 44 percent said that conduct should lead to impeachment or removal from office.

Trump’s approval rating among registered voters, according to the poll, sits at 41 percent, while 54 percent disapprove of the president.

Quinnipiac conducted the poll Oct. 11-13, surveying more than 1,100 registered voters. It has a margin of error of 3.5 percentage points.