Impeachment looms large over the 2020 election, but Trump's approval could be a bigger factor: Opinion

Trump's approval rating could make all the difference, as it has for decades.

3) The November election a year from now is going to be primarily determined by macro factors, the most important of which is the president’s job approval number on Election Day. Every president running for reelection over the last 60 years has received on Election Day a percentage of the popular vote within a point of their job approval number. For instance, Obama in 2012 had a job approval of 51% and got 51% of the vote. Bush in 2004 had a job approval of just over 50% and got just over 50% of the vote. The same was true for Clinton in 1996, Bush in 1992, Reagan in 1984 and Carter in 1980. In all these cases, the opponent was a secondary factor.

4) Considering the above, ignore the state head-to-head polls for the general election that you see at present. If you do look at state polls, pay attention to Trump’s job approval number because that is the biggest factor in whether he can carry a given state. If Trump’s approval number is below 45% in a state, he is highly unlikely to be able to carry it. If his approval number is above 49% in a state, he is highly likely to carry it. In between those numbers is highly unpredictable. I would suggest ignoring most of the state general election polling until next October.

5) The impeachment process is going to be a very disruptive moment in our country, but spelling out exactly what the political consequences will be is guesswork at this point. Trump is in a very different, and much more precarious political position, than Bill Clinton in 1998. Today, a plurality of the country supports President Trump’s impeachment and in some polls it is a majority; in 1998, support of impeachment of Clinton never got above a third of voters. In 1998, Clinton had a 65% job approval; today, Trump has less than 40%, according to the latest ABC News/Washington Post poll. A majority of the country disapproves of him and nearly two-thirds see his conduct as unpresidential -- a very problematic communication environment in the context of impeachment. Still, even having lost many Americans on impeachment, President Trump is unlikely to be convicted in the Senate because of support from Republicans unless information is revealed which fundamentally alters the GOP perception of him.

In this time of profound change, a day seems like a year of movement, and a year seems like a lifetime. So with a lifetime ahead of us until next November, let us focus on the big picture, not get drawn into reality show politics, and set our North Star to finding leaders with integrity and who can communicate on big values and how to achieve the consensus our democracy depends on.

Matthew Dowd is an ABC News analyst and special correspondent. Opinions expressed in this column do not necessarily reflect the views of ABC News.