Democrats are rightfully ecstatic that they won two of the three 2019 elections for governor in deep red Southern states, overcoming relentless campaign visits by President Donald Trump. But in truth, their twin triumphs had less to do with Trump and more to do with GOP Gov. Matt Bevin's toxicity in Kentucky and Democratic Gov. John Bel Edwards's popularity in Louisiana.

Edwards and Democratic Gov.-elect Andy Beshear ran well ahead of Hillary Clinton's 2016 support virtually everywhere in their states. But the results also reaffirmed where Democrats' true opportunity lies in 2020: suburbs with lots of college-educated whites.

Democratic victories in Kentucky (where Trump won by a huge 30 points in 2016) and Louisiana (where Trump won by 20 points), are all the more impressive because turnout skyrocketed compared to the races four years ago. In Kentucky, the number of votes cast spiked 51 percent over 2015, and in Louisiana, votes cast surged 31 percent — far higher than the 21 percent increase in Mississippi, where Democrats fell short.

But a closer look at the results suggests it wasn't necessarily higher turnout that put Edwards and Beshear over the top. In both Kentucky and Louisiana, turnout surged strongly in both heavily blue and heavily red parts of each state, suggesting both Trump and the Democrats were effective in galvanizing their supporters to the polls.

Instead, the difference-maker in both cases was big Democratic gains in those suburbs that have high shares of college-educated white voters. For example, Edwards won 57 percent in Jefferson Parish, just outside New Orleans, compared with 51 percent in his 2015 race. And Beshear took 42 percent of the vote in Boone County, just outside Cincinnati, Ohio, compared with 32 percent for Democrat Jack Conway four years prior.

Overall, Democrats' narrow wins in both races wouldn't have been possible without changing suburban attitudes. In the aggregate, blue gains in the 20 Kentucky counties and Louisiana parishes with the highest shares of whites with college degrees — concentrated in the New Orleans, Baton Rouge, Louisville, Lexington and Cincinnati metro areas — were barely enough to offset Republican gains elsewhere.

The continued migration of highly college-educated suburbs away from Republicans in the Trump era is welcome news for Democrats. The Kentucky and Louisiana results are a continuation of midterm gains for Democrats in places like the suburbs of Dallas, Houston, Phoenix, Charleston and Oklahoma City.

However, robust turnout in more rural parts of Kentucky and Louisiana is a silver lining for Trump. More critically, Democratic gains among suburban college-educated whites — and relative stagnation among other voters — could actually widen Trump's advantage in the Electoral College relative to the popular vote.

Of the dozen states where college graduates make up over 40 percent of all eligible white voters — California, Colorado, Connecticut, the District of Columbia, Hawaii, Illinois, Maryland, Massachusetts, New Jersey, New Mexico, New York and Virginia — none are likely to be decisive in the race for the Electoral College.

In other words, unless Democrats are able to retain support among other groups in states like Michigan, Pennsylvania and Wisconsin, they risk further adding to their vote-wasting problem in 2020, which could allow Trump to win re-election while losing the popular vote by 5 million or possibly more.