An inflexible math governs American political life at the current moment, grounded in ratios that control the behavior of our sovereign institutions. Republicans make up 44% of the American electorate, or 88 million people. Of these, 29.6 million (14.8% of the total electorate) cast ballots in the Republican primaries of 2016. The fate of Donald J. Trump and the nation he leads thus hinges upon the opinion of 51% of Republican primary voters, or 15.1 million people.
The reasons for this fact are easy to grasp. In 2014 Eric Cantor, the six-term Congressman serving as House Majority Leader and poised to eventually become Speaker, was ousted from his legislative seat by a primary challenger. This served notice to all GOP House members, that they live under the sword of Damocles. If any one of them sufficiently displeases the party base, particularly those activist voters who turn up for primary contests, they will be sent packing regardless of seniority or institutional leverage. Combine this with the startling hostile takeover of the GOP nominating process that Donald Trump effected in 2016, and it is clear why House GOP members will watch Trump's approval numbers very closely as they decide what to do in the face of the White House's escalating scandals.
15.1 million people (51% of the GOP primary electorate) make up about 7.4% of eligible voters. If we assume that about 1 in 4 people who answer "approval rating" polls will actually cast a vote in the primary elections (based on the 28.5% total turnout of registered voters in the 2016), Donald Trump can safely see his national approval rating fall to 30% before he lacks the support among GOP voters necessary to sway Congressional primary contests. Until his approval ratings fall to that floor or below, Trump can expect Republican voters to throw out any Representative he targets, and all GOP House members know this.
This is why, no matter how erratic or inept his conduct and no matter how much evidence of his wrongdoing comes to light, Donald Trump will not be impeached as long as Republicans control the House. Robert Mueller and his team are evidently working rigorously to investigate the Trump campaign. Given how evasive the administration has been (suggesting they have something to hide), given the proclivity of such investigations to spill over into new realms (such as money-laundering, bribery, etc.), and given the Trump Organization's reputation for unsavory dealings, the "Mueller Report" (when it eventually appears) is likely to entail hair-raising allegations, but none of that will matter. Unless and until his approval ratings fall to or below 30% (or until Democrats attain control of the House), Trump is immune to sanction.
Trump's approval rating is not likely to erode to that requisite level. Those who voted for Trump did so in full knowledge of the malignant qualities that have been on such lavish display during the months he has been in office. They knew he was ignorant, a bully, a braggart, and a liar. They knew that he had grotesquely threatened and insulted women, Muslims, Latinos, and people of color. They knew that the Russians had conspired to aid his campaign (and they now know, in the wake of Don Jr.'s emails, that the Trump campaign welcomed such support). They voted for him anyway. Nothing that has transpired since can be surprising to them.
What is going on? This polarization in the perception of Donald Trump himself has been among the most upsetting and alarming aspects of the current political scene for many observers. It is distressing, in the face of so much mounting evidence to the contrary, to see his supporters continue to describe Trump as "a good man," "a man of integrity," "strong". The discourse is reminiscent of the recent internet fracas over the color of a photographed dress, except that the disputed image in Trump's case is so much less ambiguous. Moreover, it is not merely his supporters' positive view of Trump that dismays, but their insistence that any negative perception of the president must be the product of bias or malicious intent. Discussions across that chasm of dispute can make it seem as if the world has lost its bearings altogether.
Many social, political, and economic factors obviously contribute to this moment of polarization in American politics, but the sheer intensity of disconnect between the opposing extremes cannot be explained without reference to the issue of race. Many millions of voters, swayed by messaging and rhetoric broadcast by various well-funded interests, were willing to believe that our nation had fallen into a uniquely dire cataclysm under Barack Obama, a moral and social disaster quite apart from the economic distress of the Great Recession. For many this may not have been a function of conscious racism- Obama's race triggered latent feelings and proclivities, so that voters were willing to be persuaded that he was a singular monster without being consciously aware of why they were inclined to think the worst of him. Combine this with the signs that many read in Obama's election concerning the larger racial demographics of the country, and one can see why certain voters (many of whom are affluent and well-educated) went into the 2016 election gripped by an inchoate feeling of panic.
For those voters, what was important about Donald J. Trump was not any particular plan or skill that he brought to the political stage, but the ways in which his persona gave expression to their fears and anger. His eschewal of "political correctness" validated their own anxieties about the Obama presidency. The fact that he was in almost all ways unfit for the office made him the perfect "anti-Obama" protest candidate, embodying the assertion that the one, non-negotiable requirement to be president should remain being a white male.
Again, I would not claim that these represent conscious calculations on the part of most Trump supporters. But they make sense as subconscious motivations that explain the bifurcation in the way Trump is perceived. Because they sense a disaster and they want Trump's election to be its solution, his supporters are ever inclined to give him the benefit of the doubt and attribute qualities and motives to him that others find implausible. Moreover, because they are so convinced that the Obama administration was catastrophic, waiting for Trump's diehard supporters to become disappointed with his failure to deliver "results" is likely to be a fool's errand. For many of Trump's supporters, the only thing that Trump needs to do to satisfy their sense of urgency is to be himself. Simply by being in the White House and being so obviously antithetical to its previous occupant, Trump is giving his supporters the reassurance for which they searched. He need not do anything else to please them.
All of this explains why no one should hold their breath waiting for Donald Trump to be impeached. If the Democrats should win control of the House in 2018, however, the odds change significantly. At that point the residual support Trump retains, however robust, will not be enough to protect him from impeachment if (as seems likely) the "Mueller Report" broadcasts evidence of "high crimes and misdemeanors." What Trump might do at that point, given how unscrupulous he has proven to be in every other regard, is a sobering thought. Even more distressing is the question of how his supporters will respond to whatever transpires, given their seeming refusal to see Trump in anything but a positive light.
UPDATE: An old friend and classmate on Facebook was kind enough to point out discrepancies in my numbers. I've corrected the math, but the larger point I was trying to make still stands.