There’s no mention of how much of that erosion has happened under administrations friendly to conservative Christianity, and therefore probably reflects internal weakness, division and scandal more than pressure from outside.

There’s no reckoning with the tension between the G.O.P.’s religious and libertarian wings, the clear support of many religious conservatives for the welfare state that official conservatism decries — or the extent to which Trump won the Republican nomination by running against the familiar critique of big government that Barr recycles in his speech.

And there’s no acknowledgment that a familiar tag like “moral relativism” may be a poor fit for a woke progressivism whose moral fervor is increasingly the opposite of relativist — but perhaps a better fit for a religious conservatism that has demonstrated an embarrassing, at times self-discrediting moral flexibility in its support of, well, Donald Trump.

If these and other issues complicate the thesis of Barr’s Notre Dame address, a similar accounting of trends in presidential power makes the thesis of his Federalist Society speech look totally implausible. Again, his theme is reassurance: reassuring legal conservatism that its Reagan-era vision of an executive unduly constrained by an overreaching Congress still applies to the presidency of 2019.

But it obviously, obviously doesn’t. The presidency and its powers were, indeed, weakened substantially in the aftermath of Vietnam and Watergate, which is part of why conservatism at the time reasonably sought their reassertion. But since Reagan and especially since 9/11 there has been a dramatic re-expansion of the imperial presidency, with a successful consolidation of sweeping presidential powers over war making and a more contested attempt to claim new powers over domestic policy — both of which have advanced under Democratic and Republican presidents alike.

Barr does acknowledge, because he must, the increasing abdication of Congress from its policymaking duties. But he claims that the legislature has nonetheless expanded its power over the executive, by replacing policymaking with an “abuse of the advice-and-consent process” that holds up and harasses and sometimes rejects many presidential nominees.

But the change in the advice-and-consent process reflects the weakness of Congress, not its overweening, presidency-constraining strength. An imperial presidency, by its nature, raises the stakes for presidential nominations and appointments: The fact that the president can go to war without congressional authority makes Defense and State Department nominations more fraught; the fact that presidents are constantly pushing the envelope on immigration policy or health care regulations turns Health and Human Services and Department of Homeland Security nominations into a battlefield. But all of this is happening because the presidency is more powerful than ever, leaving the people’s branch reduced to fighting over which viziers our czar gets to empower or have whispering in his ear.