Democratic presidential candidates (L-R) Sen. Bernie Sanders (I-VT), former Vice President Joe Biden, Sen. Elizabeth Warren (D-MA) and South Bend, Indiana Mayor Pete Buttigieg enter the stage before the Democratic Presidential Debate at Otterbein University on October 15, 2019 in Westerville, Ohio.

President Donald Trump finds himself in a rut in potential matchups with top Democratic challengers a year before the 2020 election, polling shows.

Former Vice President Joe Biden, Sens. Elizabeth Warren, D-Mass., Bernie Sanders, I-Vt., and Kamala Harris, D-Calif., and South Bend, Indiana, Mayor Pete Buttigieg all hold comfortable leads over the president in hypothetical contests, according to RealClearPolitics averages of national surveys. The latest poll of head-to-head races raised eyebrows: an ABC News/Washington Post survey released Tuesday showed all five of the Democratic candidates beating Trump by at least 9 and as many as 17 percentage points, a wider margin than in most other polls.

Biden fares the best against Trump, as polls find a 10 percentage point advantage for him on average. Sanders holds the second-biggest lead against the president, trailed closely by Warren. Harris and Buttigieg have the most narrow edges over Trump among the five candidates tracked by RealClearPolitics.

Here are how those Democrats currently stack up against Trump in averages of national polls:

The surveys underscore the peril Trump faces in trying to win another term in the White House, even backed by an economy strong enough that it would traditionally boost an incumbent's hopes. Dragged down by poor approval ratings on issues such as health care, immigration, foreign policy and race relations, the president appears headed for anything other than a 2020 landslide.

Though national polls offer a snapshot of Trump's current standing against his rivals, they leave major gaps in understanding what will happen in November 2020 — especially this early in the race.

Polling averages in the individual states most likely to determine who wins the Electoral College still favor Democrats. But Trump looks to have a better chance of carrying 2020 battlegrounds than winning the nationwide popular vote.

Take Pennsylvania and Michigan, two of the states that propelled Trump to the White House with narrow 2016 victories. In an average of Pennsylvania surveys, Biden, Sanders and Warren lead Trump by about 7, 5 and 2 percentage points, respectively, according to RealClearPolitics. In Michigan, Biden, Sanders and Warren have edges of about 8, 7 and 3 percentage points, respectively, over the president.

A series of swing state surveys released Monday indicate the Electoral College could swing either way. The New York Times/Siena polls gauged potential head-to-head matchups in Pennsylvania, Michigan, Wisconsin, Florida, Arizona and North Carolina — states that will play a huge role in deciding the election.

Trump performs worse in those states in hypothetical matchups versus Biden than he does in potential contests with Warren and Sanders. The vast majority of those polls show tight races a year out: Nearly all of them show a candidate with a lead that falls within the survey's margin of error.

— Graphic by CNBC's Nate Rattner