The president’s method has pretty strong support from social scientists. The overwhelming weight of recent scholarship points to two major trends in American politics over the past three decades to justify his theory. The first is that partisan polarization in Washington has greatly intensified since the 1960s. The distance that separates the parties on most issues has vastly increased. The ideological homogeneity of each party has solidified. In other words, centrists faded as a major force in politics and policy making. The second and related trend is that the phenomenon has been much more pronounced within the Republican Party. The GOP has moved further to the right than Democrats have moved to the left. Republicans are more ideologically cohesive as a party than are Democrats, who still exhibit greater division and fragmentation relative to their counterparts (although not as much as they did in the 1950s and ’60s, when Democrats were fundamentally divided between southern and northern wings).
During the 2016 election, the power of partisanship was the basis of Trump’s victory. As a candidate, Trump dismissed the pundits who predicted that his full-throated partisan appeals threatened a replay of the 1964 election, when Senator Barry Goldwater’s right-wing extremism persuaded some Republicans to vote for Lyndon Johnson.
In the end, Trump was right; the pundits were wrong. There was very little movement in the electoral map. Although a small number of Democrats voted for Trump in states such as Wisconsin, Pennsylvania, and Michigan, the real key to Trump’s Electoral College victory was that in the final weeks of the campaign—using Hillary Clinton’s email scandal as a perfect foil and capitalizing on Russian social-media hijinks to stir division—Trump whipped up Republican energy behind the ticket. The red states did not turn blue. This was essential, or his approximately 78,000-vote margin in swing states would not have mattered. Faced with the choice between Trump and Clinton on Election Day, Republicans came home.
Trump’s theory of politics has also been crucial to his success on Capitol Hill. The president has depended on the Republican Congress to protect him from investigation and to send key legislative items—such as the corporate tax cut—to his desk for a signature. Though there have been a handful of Republicans, such as Senator Jeff Flake, who enjoy criticizing the president on television, by and large Republicans have voted in unison.
Read: The Republican establishment stands behind Trump.
Trump has not left this to chance. He has been extremely aggressive staying on the campaign trail, holding rallies to build his own support and to make sure that candidates in key states understand the risk of opposing him. Many Republican candidates have declared their allegiance to the president as the head of the party. With Trump counting on the fact that Republican legislators will always come home, he has been able to employ a parliamentary governing style, in which the White House and the congressional majority act with a degree of unity that even the late President Woodrow Wilson would have admired.