Trumpism may have parallels in populist, nativist movements abroad, but it is also the culmination of a proud political party’s steady descent into a deeply destructive and dysfunctional state. ...

As political scientist Frances Lee has demonstrated, the trend toward polarization was driven not just by sharper policy differences but also by a much more competitive struggle for control of the levers of power. Unlike the situation through most of the past century, both parties now had a reasonable shot in most elections at winning the White House and Congress. There were fewer presidential landslides and fewer extended periods of one-party control of the House or Senate. Pressure built for more party loyalty in Congress; legislating became more than ever driven by the permanent campaign.

These polarized parties could and did act decisively when one of them controlled both ends of Pennsylvania Avenue. But the more frequent periods of divided party government inspired willful obstruction and policy avoidance.

Why then single out the Republican Party as an insurgent outlier? Newt Gingrich, first among other Republican leaders, took this polarization to a new level. He was key in the transformation of the party into a destructive and delegitimizing force in American politics (which makes his recent bonding with Trump very fitting).

From the time he came to Congress in 1979, Gingrich deployed a strategy to break the Democrats’ stranglehold on power in the House by moving to polarize the parties, to use the ethics process to taint both the majority and the entire political process, and to get Americans so disgusted with politics and politicians that at the right moment, they would rise up and throw out the incumbent party.

A decade into his tenure, Gingrich was able to seize on and exploit a wave of populism triggered by a proposed 25 percent pay raise for members of Congress, judges, and top executive officials — a raise, ironically, Gingrich himself supported. The move ignited a broad national anger, empowering such diverse figures as Ralph Nader, Pat Buchanan, and, later, H. Ross Perot, and solidifying talk radio under Rush Limbaugh as a political phenomenon.

When populism exploded again with the 2008 financial collapse and TARP bailout, the next generation of Republican leaders — led by Eric Cantor, Kevin McCarthy, and Paul Ryan, the self-named Young Guns — took the Gingrich playbook and ran with it, exploiting and fueling populist anger at the political establishment and the new black president to take back power. ...