Washington (CNN) President Donald Trump would face competitive general election races against each of his top three potential Democratic challengers in seven battleground states he won in 2016, according to new polls released Monday, about a year from the 2020 general election.

The polls from The New York Times Upshot and Siena College surveyed registered voters in the states -- Michigan, Arizona, Florida, Iowa, North Carolina, Wisconsin and Pennsylvania -- and found that just four of the 21 potential matchups showed a lead for one candidate outside the survey's margin of sampling error. Former Vice President Joe Biden is leading Trump 50% to 45% in Arizona, while Trump is leading both Vermont Sen. Bernie Sanders and Sen. Elizabeth Warren in Iowa. In Michigan, the President tops Warren 46% to her 39%.

With the general election less than a year away, and three months until the Iowa caucuses -- the first real test of the 2020 Democratic primary -- the new data provides a useful look at how the three Democratic front-runners could fare against the President next November in some of the closest-watched states of the election. The numbers also come a day after three national polls suggested that Biden, Warren and Sanders are leading the pack of Democratic candidates. Most national polling also shows those three holding sizable leads over Trump among registered voters nationwide. But Trump won the presidency despite losing the popular vote in 2016, largely due to his success in the states included in the new polls.

In three states, Warren fared significantly worse than Biden against Trump. Biden got 46% support in Florida, while Warren had 41% there. In Michigan, Biden had 44% support while Warren had 39%. She also lagged behind Sanders here, who had 45% in his matchup with Trump. And in Iowa, Biden's support was at 44% while Warren's was at 40%. Trump's support in each of those matchups holds about even across Democrats.

The surveys also tested a generic Democrat against the President, asking whether voters would definitely or probably vote for Trump or the Democratic nominee. Those potential matchups were also close in nearly all seven states, though the Democrat had an edge outside the error margin in Wisconsin with 46% to Trump's 40%.

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