In the hours since Justice Ruth Bader Ginsburg's passing, several analysts have speculated the new, colossal Supreme Court fight will help President Trump by rallying traditional GOP voters behind him and shifting the focus of 2020 from the mismanagement of COVID-19 to a more straightforward partisan cage match. 

That's possible, but given the likelihood of the court to take a sharp right turn, a pre-election Supreme Court fight carries much bigger risks for Trump than the Brett Kavanaugh brawl in 2018.

Namely, there's potential for the Roe v. Wade/abortion issue and the Affordable Care Act to drive a wedge in Trump's coalition. In 2016, much of his support came from voters who disliked Hillary Clinton, liked Trump's rhetoric on trade and immigration, but consider themselves pro-choice — especially non —evangelcial, blue-collar women. And, these voters remain up for grabs in 2020.

This morning, I dove into data from the 2016 Cooperative Congressional Election Study (CCES), a 50,000-plus person national survey conducted by YouGov. The survey measured voters' attitudes towards the abortion issue on a six-question scale. Specifically, it asked voters whether they support or oppose the following:

  1. Always allow a woman to obtain an abortion as a matter of choice
  2. Permit abortion only in cases of rape, incest or when the woman's life is in danger
  3. Ban abortions after the 20th week of pregnancy
  4. Allow employers to decline coverage of abortions in insurance plans
  5. Prohibit the expenditure of funds authorized or appropriated by federal law for any abortion
  6. Make abortion illegal in all circumstances

I rated anyone who chose the pro-choice or pro-life side on four, five or six of these questions as at least "leaning" towards that position, and labeled voters who split their answers evenly down the middle as having "mixed" views.

Not surprisingly, 74 percent of Clinton's voters at least leaned pro-choice, while only 15 percent leaned pro-life and 11 percent held mixed views. But only 65 percent of Trump's voters at least leaned pro-life, while a substantial 22 percent at least leaned pro-choice and 13 percent held mixed views. Among third party voters, views on abortion were almost evenly split.

Although Trump downplayed the abortion issue in 2016 in favor of more populist economic messages on trade and immigration, voters with mostly pro-choice attitudes made up more than a fifth of his support in plenty of battleground states: 25 percent in Iowa, 24 percent in Florida, Michigan and Pennsylvania, 21 percent in Arizona and 20 percent in Ohio and Wisconsin. 

For decades, many of these blue-collar, pro-choice Trump supporters had voted for Democrats because they saw Republicans as a coalition of corporatists and "Bible thumpers" who sermonized against abortion and same-sex marriage. But in 2016, many of them yearned for an anti-elite outsider and when Trump came along, they didn't mind him as much.

Today, there may be an opportunity for Joe Biden to win back many of these Obama-to-Trump defectors by tying Trump to the "DC swamp:" Sen. Mitch McConnell and the establishment Republicans who want to "end Roe v. Wade, cut taxes for billionaires and strike down the Affordable Care Act during a pandemic." In fact, polls show Biden already winning a robust share of these blue-collar voters.

The populist message Republicans should be most scared of probably goes something like: "In 2016, Trump promised to drain the swamp. Instead, he became the swamp: he let Mitch McConnell and stock-dumping, ultra-far right GOP senators write his entire domestic agenda." But today, few ads by Biden or Democratic outside groups have attempted to make this link.

It's also not clear groups like the Lincoln Project, whose ads mainly feature over-the-top anti-Trump messaging that amounts to political porn for base Democrats and "Never Trump" Republicans, understand this type of swing voter.

The bottom line: the millions of Obama-to-Trump voters who will decide the 2020 election in Michigan, Pennsylvania, Wisconsin and elsewhere tend to tune out attacks on Trump as a divisive or bad person. But they've long despised McConnell, "establishment" Republicans and the religious right — and a SCOTUS fight gives Democrats an opportunity to rip Trump's coalition open.

More from the Cook Political Report