They found that while opinions of the president have been very consistent since 2016, “Obama-Trump voters have had a significant change in their view of President Trump over the last two years. In the 2016 VOTER Survey, more than 8 in 10 (85 percent) Obama-Trump voters held a “favorable” view of the president — 19 percentage points higher than in 2019 (66 percent).” In other words, while Obama-Trump voters still overwhelmingly approve of the president, that support is a lot softer than it was back in 2016. They did not find any significant movement among any other group of voters (like those who supported Romney in 2016 and Trump in 2016, or those who voted Romney 2012 and Clinton in 2016). And, while these Obama-Trump voters remain supportive of the president, “even small movement among these voters — who represented 5 percent of voters in 2016,” writes the authors of the report, “may prove significant heading into the 2020 presidential election.”

In an analysis of the 2018 election Yair Ghitza, chief scientist at the Democratic data firm Catalist, makes the case that while turnout was a key factor in Democrats success in 2018, “a big piece of Democratic victory was due to 2016 Trump voters turning around and voting for Democrats in 2018.” In 2016, Hillary Clinton won the popular vote by 2 points. In 2018, Democrats won the national vote by 7 points. Ghitza’s analysis finds that almost 90 percent of that 5 point difference in vote margin came from voters who supported Trump in 2016, but voted for a Democrat in 2018. CNN’s Ron Brownstein does an excellent job of explaining the methodology and the findings of this Catalist study in his recent CNN column.