As Trump has won additional contests in every region of the country, many commentators have openly wondered what impact (whether good or bad) a Trump candidacy will have on the Republican ticket down ballot. When digging into the results of his recent victories, it becomes clear that a Trump candidacy could be a disaster for several Republicans currently in marginal districts.

To win back the U.S. House, Democrats must score a net gain of 30 seats. Redistricting virtually assures a two-seat net gain (Florida’s 10th and 13th) and Democrats can also expect to pick up the new 4th district in Virginia, where the incumbent, Randy Forbes, has fled to the 2nd District.

The details of Trump’s victories in states like Florida, Illinois, Michigan, and Virginia reveal the impact his nomination could have on the upcoming House races.

Florida

Donald Trump won 45.7 percent of the Florida vote. But his performance in two heavily Cuban districts in South Florida (which generally favor Democrats in other races) could be reason for anxiety at the NRCC. Trump won just 26.5 percent in the 26th District, a swing district currently held by Carlos Curbello, and he won just 21.9 percent in the 27th district represented by incumbent Ileana Ros-Lehtinen. Support for home state Cuban-American US Senator Marco Rubio obviously skews the results to some extent, lowering Trump’s vote share. Yet, Curbello has already signaled he can’t support Trump in the general election. Does this mean that the Republican advantage among Cuban-American voters is coming to an end? Maybe, maybe not. But it is, at least temporarily, in the abyss due to Donald Trump’s candidacy.

Illinois

Similar themes can be seen in Illinois. Donald Trump won Illinois by more than 8 points over Ted Cruz, with John Kasich garnering 19.7 percent statewide. However, in the competitive 10th district, where Brad Schneider is seeking to regain a seat lost in 2014, optimism is growing that Trump is exactly the type of candidate who will fail miserably with upscale Illinois voters. Results in suburban precincts of Cook County and Lake County should be cautionary for Republicans.

A Trump Nomination Puts Several Districts In-Play

Virginia

The pattern discernible in Illinois’ suburban precincts was even more pronounced in Northern Virginia. While Trump narrowly won the overall Virginia vote, he lost by 7.7 points in the 10th Congressional District, the key bellwether in the state. Trump’s struggles in Loudoun County, the largest segment of the 10th District, underscore how Trump could cause problems for down ballot Republicans. Loudoun County is a fast-growing and diverse community, where Trump lost by 12.4 points. Based on its makeup, this community is unlikely to support Trump in the fall. Trump’s effect also has the potential to jeopardize GOP incumbent Barbara Comstock, generally considered a vulnerable but not top-tier target.

Minnesota

Even in Minnesota, where Marco Rubio won the state’s caucus, Trump received 19 percent in the suburban 3rd Congressional District (2.4 points below his anemic 21.4 percent statewide result). Do these conditions suggest that Republican incumbent Erik Paulsen is vulnerable in the fall? If so, the result could also complicate Republican chances in the open 2nd Congressional District, currently held by arch-conservative John Kline. That district is also in play, and not expected to be welcoming to Donald Trump.

Ohio

An oft-overlooked marginal district is the 14th in Ohio (home of suburban enclave Lake County) where more than one-third of the voters have a college degree or higher. Should the conditions outlined above remain consistent, David Joyce, the Republican incumbent, might face a formidable challenge in the general election with Donald Trump heading the ticket.

Michigan

Trump’s strong statewide victory in Michigan—almost 12 points ahead of Ted Cruz—obfuscates the fact that he lost to Cruz in Michigan’s 6th District. Barack Obama won there in 2008 but narrowly lost to Mitt Romney in 2012. As a candidate, Romney was far more advantageous for the Republican incumbent Fred Upton than Trump would be.

This scenario could be vastly different should establishment Republicans run a third candidate for president, as has been whispered recently. A third Republican candidate would attract additional conservative voters who would likely support a Republican candidate down-ballot.

Until recently, the prospects of a Democratic takeover of the House were, at best, unlikely. But with Republicans already straining to hold swing seats won in the 2014 midterm election, we anticipate that a Trump nomination would weaken their ability to control the House this November.