1. Donald Trump is above the law.
2. He is above the law because the Republican Party has decided to shield him from the consequences of any of his actions, for partisan political reasons, and a unified party with at least 1/3 of the Senate has the power to do so. They have outward unity and majorities in both chambers.
3. Brett Kavanaugh does believe that Republican presidents should be above the law. His writings make no partisan distinctions, but they are clear, and nobody like Kavanaugh should be trusted to be nonpartisan in the application of such crass statements of total executive immunity, given how the GOP flips back and forth on the principles of the "unitary executive."
4. There is a 100% chance that, as part of the vetting process, Kavanaugh was questioned extensively and gave something close to an assurance that he would rule in Trump's favor on any questions of constitutionality/criminality/prosecution-type stuff. When Trump made his decision, the strength of the guarantee he received from each person interviewed was the primary determinant of his decision. Period. How explicit was the questioning and guarantee? It would have been done with just enough of a wink and a nod to satisfy Kavanaugh's need to pretend that he has a conscience and real principles. As I keep writing, though... costumed politicians.
5. On the Court, Kavanaugh will, should it become necessary, ensure that Donald Trump faces no legal consequences for anything he has ever done. He will rule for executive power any time the president has an R after his name, and only ask more detailed questions if there's a D after a president's name. Assuming the country makes it past this mess...
In other words, Brett Kavanaugh is a craven liar. I won't pretend otherwise, and neither should you. My tolerance for pretense, theater, and bullshit has been exhausted completely.