President Donald Trump was likely helped in the 2016 election by the fight over a Supreme Court nomination. Similarly, Republicans were likely aided in the 2018 Senate battle by the nomination and eventual confirmation of Justice Brett Kavanaugh.
We don't know what the ultimate effect of any Supreme Court battle will be on the 2020 election. Still, we can look at the playing board. It suggests the 2020 electoral calculus has fundamental differences with the electoral math of 2016 and 2018 when it comes to Supreme Court nominations.
Yesterday, I noted that more of former Vice President Joe Biden's supporters have said the Supreme Court was important to their vote than Trump supporters. That's very different from 2016, when Trump backers said the court was more important to their vote than Hillary Clinton backers.
The contrasts go deeper than that, however.
Trump often struggled with rallying the base in 2016. There were points in that cycle when he was receiving only about 75% of the Republican vote in polls. A Supreme Court nomination was the perfect way to get the base to support his cause.
Trump, though, has centered pretty much his entire presidency around appealing to his base. He's done so, oftentimes, at the expense of bringing in more moderate voters to his cause. It's paid off for Trump.
Republicans are backing Trump at very high numbers now. A NPR/PBS NewsHour/Marist College poll out on Friday put Trump's support at 94% among likely Republican voters. Our last CNN/SSRS poll showed that 99% of very conservative Republicans were supporting Trump.
In other words, Trump already has the base behind him in a way he didn't at many times in 2016. Any more gains he could make with them would be very limited.
There are distinctions between the 2018 and 2020 Supreme Court nomination showdown as well.
You may recall Republicans picked up four Senate seats and lost two for a net gain of 2 in 2018. This came after Kavanaugh was nominated in late summer and confirmed early that fall.
It does seem like the Kavanaugh nomination was a boon to a number of Republican Senate candidates. Republicans knocked out Democratic senators in Indiana, Missouri and North Dakota. In all of those states, a majority of voters who said that Kavanaugh was a factor in their vote cast their ballots for the Republican Senate candidate. Those who said it wasn't a factor either split their vote or a majority went for the Democratic nominee.
All of those seats were in states where Trump won by 19 points or more in 2016. That is, they were very red states.
The Kavanaugh hearing, if anything, rallied the Republican base in red states.
In the only purple state where Republicans defeated a Democratic senator (Bill Nelson in Florida), voters who said his vote against Kavanaugh was a factor in their decision were actually slightly more likely to back the Democratic nominee.
The 2018 House elections tell a similar story. Unlike in the Senate, where a limited number of seats is up every cycle, every House seat was up for election in 2018.
House Republicans were not helped by the Kavanaugh hearings.
Democrats' advantage on the generic congressional ballot was in the high single digits before the Kavanaugh hearings and remained as such through the election. Democrats ended up with a net gain of 40 seats in the House.
The 2020 presidential race will be fought on, if anything, more favorable terrain than the 2018 House elections. Democrats don't need to worry about winning a majority of congressional districts. They only need to win a majority of electoral votes.
Likewise, the 2020 Senate terrain is totally different. Only one of the seats Democrats are defending is in deep red territory. That Alabama seat was already in major danger of flipping prior to any Supreme Court battle.
Meanwhile, the Democrats' easiest path to a Senate majority runs through purple states. Democrats' easiest pickup opportunities are in Arizona (a state where the same Republican Senate candidate lost in 2018), Colorado and Maine. Biden is clearly ahead in the polls in all of these states.
The other two best pickup opportunities are in states where Trump is likely either up by a point or two (Iowa) or down by a point or two (North Carolina). In neither state is the Democratic Senate nominee running too far ahead of Biden.
The bottom line is that, while any estimates of what the upcoming Supreme Court fight means for the election are just guesses, 2016 and 2018 are not good road maps to understanding the dynamic in 2020. The situations are quite different.