The survey found the presumptive Democratic presidential nominee leads the incumbent by a 48% to 45% margin across Arizona, Florida, Michigan, North Carolina, Pennsylvania and Wisconsin, which will determine who wins the White House in November. Biden's edge grew from 1 percentage point in the last swing-state poll released two weeks ago. Trump led in all previous versions of the survey dating back to March.
The poll released Wednesday found Biden leading Trump in all six states for the first time (though only narrowly in some):
The CNBC/Change Research poll surveyed 2,408 likely voters across the six states from June 12-14 and has a margin of error of plus or minus 2 percentage points.
The result adds to a series of warning signs for Trump less than five months away from the election. Biden's lead in averages of both national and swing state polls has widened in recent weeks as the Trump administration struggles to contain the coronavirus pandemic and meet nationwide calls to address police brutality and systemic racism.
Trump's approval rating has also reached its worst level since February 2019, according to a FiveThirtyEight average. About 41% of respondents to recent surveys compiled by FiveThirtyEight approve of the president, while 55% disapprove.
Of course, the deficit Trump faces in key electoral college states is hardly insurmountable, and he still has more than four months to make up ground.
The CNBC/Change poll found 45% of likely voters in the six states approve of how Trump has handled the coronavirus, while 55% disapprove. On police violence and discrimination, 44% approve of the job the president is doing, while 56% disapprove.
A majority of respondents, 52%, said Trump's response to the police killing of George Floyd and protests for criminal justice reform was harmful. Only 23% said it was helpful.
The survey also asked who voters prefer to handle a range of issues. They gave Biden and Democrats the edge on handling the coronavirus, putting the middle class first, making health care more affordable, addressing police violence and discrimination and bringing the country together during times of crisis.
Respondents preferred Trump and Republicans on the economy and getting people back to work. Likely voters were split on who would better help their pocketbooks.
— Graphic by CNBC's John Schoen