INDIANAPOLIS - With the House readying an impeachment vote for President Trump and Watergate analogies everywhere, it seems worthwhile to revisit a piece I wrote in August 2018. In it, I used historical data to show that in the modern era, national waves which favor the Democratic Party don't typically wash ashore in Indiana. But that came with an important caveat: "...[R]ecent Democratic waves that upended Washington – with the exception of the Watergate-fueled wave in 1974 – haven’t translated to Indianapolis." This raises the question: If the Trump impeachment proceedings play out like the Nixon proceedings, what does history tell us to expect in 2020? Well, the past can be a good guide for understanding where the present might be taking us, but only in a probabilistic sense. We can't use it to predict what's going to happen in 2020, but we can take a closer look at 1974 to understand exactly how the impeachment proceedings and resignation of Nixon impacted Indiana elections. That might tell us how likely we are to be heading towards a similar scenario, or at least what it would take to come close to recreating it here. We'll start with the big picture, and then drill down into individual races. Unlike 2020, 1974 was a midterm election year. We know that midterms tend to be bad for the party that controls the White House (especially in second terms, as 1974 was). Usually, the president's party loses seats in Congress, and it's not a coincidence that five of the seven national waves we've seen in the past 50 years have been in midterm election years (1974, 1982, 1994, 2006, 2010).For various reasons, presidential election years are less susceptible to waves, and tend to happen only when there is an overwhelming sense that America is headed in the wrong direction (1980 and 2008).