Was There are Red Wave Downballot in 2020?

Some people are arguing that the 2020 election results were a "red wave" aside from the presidential election, and this indicates voter fraud in the presidential election.

Even if this were true, it would not prove voter fraud.  It could just be that some segment of normally R voters refused to vote for the president, but still voted R downballot.

But was 2020 a red wave?  In the senate, Rs lost two seats (AZ, CO) and picked up one (AL) for a net loss of one (pending the outcome of the Georgia runoffs).  The results of the senate races and the presidential race were the same in all but one state.  The one exception was Maine, where Susan Collins is a popular moderate incumbent who regularly outperforms the top of the ticket.

Comparing R senate candidates' margins to Trump doesn't reveal an obvious pattern.  Trump did better in some states, while R senate candidates did better in others.  Patrick Ruffini made a map illustrating the differences.

Senate GOP vs. Trump performance by county in ballots cast so far, by county. Orange = Trump outperform. Even as margins shift, this metric should hold up. pic.twitter.com/7c3FitXlrQ

— Patrick Ruffini (@PatrickRuffini) November 6, 2020

In particular:

Trump did better than R incumbents in: AZ, ID, IA, KY, MS, MT, OK, SC
R incumbents did better than Trump in: AK, AR, CO, GA, LA, ME, NE, NC, SD, TX, WV
Trump did better than R challengers in: AL, DE, KS, MA, NH, NJ, OR, RI, VA
R challengers did better than Trump in: IL, MI, MN, NM, TN, WY

In the US house of representatives, Rs picked up 14 seats (CA-21, CA-25, CA-39, CA-45, FL-26, FL-27, IA-1, IA-2, MN-7, NM-2, NY-11, OK-5, SC-1, UT-4), and lost 3 seats (GA-7, NC-2, NC-6), none incumbents, for a net gain of 11 seats (with NY-22 still undecided).  It appears that Biden won 224 seats and congressional Ds won 222 seats.  There were some Trump/D seats and some Biden/R seats.  Left Coast Libertarian at RRH Elections notes that:

Joe Biden got 80,048,633 votes. Congressional Democrats got 76,298,374.

Donald Trump got 73,902,347 votes and Republicans got 72,542,282.

So Democrats got 95% of Biden’s vote total and Republicans got 98% of Trump’s vote total. If we average them Democrats underperformed by about 1.1 million votes. That’s a really small number of votes. It shouldn’t be unexpected that one party would do slightly better.

So how is it possible that Rs picked up seats?  Rs picked up seats RELATIVE TO 2018.  In 2018, Rs lost 42 seats from 2016.  Thus Rs lost house seats since 2016, the last time Trump was on the ballot.  Note that all but two seats that Rs picked up in 2020 were seats that Rs lost in 2018.

Some have noted that Rs won all tossup house races (according to the New York Times).  But this just indicates that the election raters did a bad job, likely due to relying on bad polls.  The conservative-leaning RRH Elections did much better, though still leaning too D.  My own ratings of Michigan elections were very good, as I did not rely much on polls.

Rs picked up two state house chambers, both in New Hampshire.  This was apparently due to the popularity of incumbent R governor Chris Sununu, who campaigned heavily for R state legislative candidates.  Rs flipped a modest number of state legislative seats, further picking up rural seats in states like KY and WV, and flipping back some seats that were lost in 2018.

Overall, the 2020 election results were slightly worse than in 2016, but significantly better than in 2018.  There was no inconsistency between the presidential election and downballot results in 2020.