The most profound change in voter registration over the past two decades was a massive increase in Democratic registration, and an accompanying decline in Republican registration, that was part of a large increase in voter registration leading up to the 2008 election. This change was consequential and ushered in a roughly ten year period of Democratic success in statewide elections. Between 2008 and 2018, Democrats won two of three Presidential races, two of three gubernatorial races, two of four senate races, two of three Attorney General races, and were six for six in the Auditor General and Treasurer races. That adds up to 14 wins in 19 races (74%).
The large registration advantage held by Democrats has slowly eroded since 2008 and has returned them to an advantage that is similar in size to the one they held at the turn of this century. This could be consequential: despite having a Democratic voter registration advantage from 1960 to 2000, the state had a Republican bias in electoral contests–Democrats won only 46% of statewide elections in the state during this time period.[ii]
In fact, the Republican’s electoral success in this era raised questions about whether the state’s voter registration statistics reflected the actual partisan disposition of the state’s voters.[iii]
It is too soon to tell if the impeachment trial of President Trump will lead to an advantage for Democrats in this state, but it is difficult to imagine that the trial will produce a change in registration that is anywhere near as consequential for state elections as the one produced by the Great Recession.