Last Tuesday, former Vice President Joe Biden scored a big win in Michigan, and he now finds himself as the overwhelming favorite in FiveThirtyEight’s forecast with a greater than 99 in 100 shot of winning a majority of pledged delegates. Biden’s strength in Michigan, as well as in Minnesota on Super Tuesday, augurs well for his chances, too, against Sen. Bernie Sanders in the two contests happening in the Midwest on Tuesday: Illinois and Ohio. These states have the sixth and seventh-most pledged delegates, respectfully, of any state or territory, making them particularly important in the delegate battle between Biden and Sanders. (You can read more about what our forecast shows for Tuesday’s other two contests, Arizona and Florida, in our Sun Belt preview here.)
Biden is a favorite in both — based on his performance elsewhere in the Midwest and the fact that he’s up by at least 20 percentage points in our polling averages of both Illinois and Ohio. But there’s still some uncertainty clouding our view of these races because we don’t actually have much recent polling in either state — just three March polls in Illinois and just one March survey in Ohio. So our forecast is relying quite a bit on what has happened in previous contests and the demographics of both states.
Let’s start with Illinois; with 155 pledged delegates at stake, it’s the larger of the two primaries. Our forecast gives Biden a better than 99 in 100 shot of finishing first. On average, his forecasted vote share is 63 percent, which means he should win the lion’s share of Illinois’s 54 statewide delegates. Sanders is projected to win an average of 33 percent of the vote — a far cry from the 49 percent he earned in the Illinois primary in 2016, when he narrowly lost to Hillary Clinton by just 2 points.
As for Illinois’s remaining 101 pledged delegates, they are allocated based on the result of each of the state’s 18 congressional districts. Biden leads by at least 16 points in every district, which speaks to his overall advantage in the state. But Sanders should also clear the 15 percent delegate threshold in every district, which means he should pick up at least some delegates.
As in other states, Biden’s best districts are the ones where black voters make up a large share of the electorate — understandable given his strong support among black voters. He is projected to surpass 70 percent in the three Illinois seats that are at least 45 percent black — the 1st and 2nd Congressional districts centered on Chicago’s southside and the 7th Congressional District in central and west Chicago. But Biden also outperforms his statewide projected vote share in two fairly white districts far from Chicago — the 17th Congressional District along the Iowa border and the 12th Congressional District by Missouri. Both seats have large percentages of whites without a college degree, which as a group, has backed Biden more this year than Sanders.
Sanders doesn’t lead anywhere, but he is notably stronger in some seats. Perhaps unsurprisingly, given his strength with Hispanic voters, his three best districts have the largest Hispanic populations in Illinois — the 4th Congressional District (70 percent Hispanic), the 3rd Congressional District and the 8th Congressional District (both about 30 percent Hispanic), which are all in and around Chicago. Sanders also tends to have higher projected vote shares in more affluent districts, which helps explain his numbers in the 5th and 6th Congressional districts (also in the Chicago area), as well as the 14th Congressional District (which is on the periphery of Chicago). These three seats rank as the wealthiest districts in Illinois by median income.
Turning to the east, Ohio is also voting on Tuesday, and it has 136 pledged delegates up for grabs. Our forecast gives Biden a 97 in 100 shot of victory, leaving just a 3 in 100 shot for Sanders. The statewide vote will allocate 47 of the Buckeye State’s delegates, and Biden’s average forecasted vote share in our model is 59 percent compared to Sanders’s 34 percent.
The other 89 Ohio delegates come from the state’s 16 congressional districts, and Biden seems on his way to winning every seat. Based on the model’s average forecasted vote share displayed in the table below, Biden leads by 17 points or more in every district, though Sanders should clear the 15 percent threshold across the map, picking up some delegates.
Biden’s strongest districts in Ohio once again tend to have the largest share of black voters, making his best seat the 11th Congressional District, which covers parts of Cleveland and Akron and is the only majority-black district in the state. The other two districts where he’s above 60 percent are both at least 20 percent African American — the 1st Congressional District (partly in Cincinnati) and the 3rd Congressional District (Columbus). Still, Biden is well-positioned to win the remaining districts, which are all at least 75 percent white.
Sanders’s best seats in Ohio tend to be whiter and somewhat more affluent. They are somewhat geographically disparate, however: His most promising seats, per our forecast, are the 16th Congressional District, mostly south of Cleveland; the 5th Congressional District in the northwest corner of the state (the only seat Sanders carried in the 2016 Ohio primary); and the 12th Congressional District north of Columbus in the center of the state.
If the Michigan result last Tuesday is any sign, the two Midwestern contests in Illinois and Ohio will likely produce comfortable wins for Biden. It’s just hard to find good news for Sanders — he looks unlikely to have a shot at winning a district in either state, and he’ll need something unexpected to happen if these primaries are to help him turn things around.