Joshua Lott/Getty Images)
Hillary Clinton in Chicago.
A new Ballotpedia poll of swing state voters released on Tuesday found Clinton leading Trump by significant margins in a number of key battleground states.
According to Tuesday's poll, Clinton leads Trump 51% to 37% in Florida, 45% to 41% in Iowa, 48% to 38% in North Carolina, and 45% to 38% in Virginia.
The poll, conducted June 10 to 22, also significantly undermines Trump's argument that he can reach the 270 electoral college votes needed to clinch the presidency by mobilizing white working class voters "Rust Belt" states. According to the Ballotpedia poll, Clinton led Trump 50% to 33% in Michigan, 46% to 37% in Ohio, and 49% to 35% in Pennsylvania.
The margin of error was plus or minus 4 points for Florida, Iowa, Michigan, North Carolina, and Pennsylvania. It was plus or minus 3.9 points for Virginia and Ohio.
Not all the polling news on Wednesday was bad for Trump.
A new Quinnipiac University poll of 1,600 registered voters nationally found Trump and Clinton in a dead heat, with the former secretary of state leading but just two points, well within the survey's margin of error.
Still, other national polls found the presumptive Democratic presidential nominee in much better standing.
A new Washington Post/ABC and Reuters polls published over the weekend found Trump trailing Clinton by double digits, while a NBC/Wall Street Journal poll found the real-estate magnate trailed Clinton by 5 points, down from 3 points in May.
Despite Clinton's significant lead, many voters in recent surveys remain pessimistic about both candidates.
"It would be difficult to imagine a less flattering from-the-gut reaction to Donald Trump and Hillary Clinton," Quinnipiac University Polling assistant director Tim Malloy said in a press release. "This is where we are. Voters find themselves in the middle of a mean-spirited, scorched earth campaign between two candidates they don't like. And they don't think either candidate would be a good president."
Many polling analysts caution against relying too heavily on state polls several months out from the election, since regular public polls of swing states are still fairly rare.
"Generally, it would be ideal to watch battlegrounds such as Ohio/Florida/Pennsylvania. However, state polls are sparse," Princeton University polling expert Samuel Wang told Business Insider in an email earlier this month. "This year's states are mostly correlated with 2012, so there's no realignment. This means that watching national numbers is probably a reasonable substitute."