More than half of Americans don't think Donald Trump is fit to serve as president, yet he has a clear path to winning re-election.

If Trump isn't removed from office and doesn't lead the country into some form of global catastrophe, he could secure a second term simply by maintaining his current level of support with his political base.

We have entered a new era in American politics. The 2016 election exposed how economic, social and cultural issues have splintered the country and increasingly divided voters by age, race, education and geography. This isn't going to change.

What have changed are the political fault lines that have driven the debate since the early 1980s. Until now, the ideological divides between the parties were largely differences around social issues, defense spending and trade, as well as tax cuts for the wealthy and corporations. Today, the central issue has become populism as voters have moved away from the two political parties and increasingly self-identified as independents.