Biden holds early edge in ABC News’ Electoral College race ratings: ANALYSIS

Former Vice President Joe Biden holds a discernible -- though not insurmountable -- Electoral College advantage over President Donald Trump, with multiple paths to the presidency but little margin for error, according to ABC News’ initial ratings for the 2020 general election.

With this weekend marking 100 days to Election Day, ABC’s race ratings place 279 electoral votes as either solidly or leaning Democratic -- slightly more than the 270 electoral votes needed to secure the presidency. Another 72 electoral votes are rated as toss-ups, while 187 are either solidly or leaning Republican.

The race ratings are determined by the ABC News Political Unit based on high-quality public polling and reporting from inside the campaigns and from outside groups involved in the presidential race.

Each state is assigned one of five categories that reflect the likelihood of it supporting a particular party ticket: solid-Republican, solid-Democrat, lean-Republican, lean-Democrat and toss-up. These ratings are designed to be dynamic, and race ratings will be updated weekly through the summer and then more frequently as November nears.

ABC News is also unveiling an interactive election map that allows viewers to make their own predictions and compare them against historical results and political experts’ picks.

The ratings show the extent to which Trump’s campaign has been forced into a defensive posture and is primarily trying to hold states that voted Republican four years ago. Trump secured 306 electoral votes in his race against Hillary Clinton in 2016, winning the presidency -- in part -- by taking longtime Democratic strongholds: Pennsylvania, Wisconsin and Michigan.

Biden could win this year by taking those states back, though losing any of them could put Trump either over the top or within striking distance of the presidency. Michigan, Pennsylvania and Wisconsin are all lean-Democrat states 100 days out, though the landscape can easily shift substantially over the next three-plus months.

The ratings also highlight the other potential paths to the presidency for Biden -- avenues that are already tempting his campaign to expand the map. Biden could withstand losses in the upper Midwest or pad his winning margin by stitching together wins in newly competitive Sun Belt states.

Arizona, Florida and Georgia are currently toss-up states, and even Texas has lost solid-Republican status and is now merely lean-Republican. Ohio is also lean-Republican, after going decisively for Trump in 2016.

Maine and Nebraska award their electoral votes by congressional district and give two additional votes to the statewide winner. One district in both states is potentially in play, as rated by ABC News.

The race ratings show a few opportunities for Trump’s campaign to go on offense, though not many. Of the states carried by Clinton four years ago, all are solidly Democratic except for New Hampshire, Nevada, Minnesota and Maine, which are leaning toward Biden for now.