This week, Washington is funereal. Today, the city halts, the National Cathedral in repose as a pulpit of mourning. Partisanship ebbs from Capitol Hill. A White House muted. These are the traditions, pageantry and rhythms of the death of a president.

The 41st president did not really understand 45th. Early in the 2016 campaign, Bush’s former chief of staff John Sununu, a former governor of New Hampshire, was trying to grapple with the Trump ascendancy he was witnessing – the continued progress of this unconventional disruptor who was upending all the norms of Republican philosophy to seize control of the party, Trump was remaking the party in his own image as he proceeded. Sununu said Trump was demeaning of the office he was seeking and that he had trouble comprehending Trump’s defiance of the laws of political physics that were thought to apply. How could the Republican Party nominate for president a man who insulted and pilloried all his opponents, and the party’s previous nominees, and the Pope?

Taking it all in, the 41st’s disdain for Trump was crystal clear. For the Bushes, Trump obliged in kind. In 2016, he attacked Jeb Bush mercilessly, and accused him of bringing his “mummy” in to help him. Trump has been scathing of the presidency of George W. Bush. The family barred Trump from the matriarch’s funeral in April.

The tectonic issue here is Trump’s strategic intent to divorce the Republican Party from its internationalism and its capitalism: its historic support for free trade and open markets abroad, and opposition to state capitalism at home. Its commitment to a global presence, undergirded with multilateral strategic and defence alliances for the United States across the world; for confronting authoritarian leaders and regimes, especially Russia. For Trump, that is history.

At this high affair of state that is today’s funeral, the not so subtle subtext will be: are the 41st and 43rd the last true Republican presidents? Will their mantle survive the 45th’s deviancy? Or will the party continue to be remade in Trump’s image no less in scope and reach than what Reagan did beginning 40 years ago?

Today will be a more muted replay of what we witnessed when Senator John McCain died, with the jagged and jarring rebukes delivered over his casket to Trump – his character, what he stands for, and where he is leading the country.

The 43rd did not invite the 45th to speak a eulogy for the 41st.

As one president is laid to rest, the launch of the next presidential campaign is imminent. One of the most telling markers of how Trump will fare in 2020 will be whether, with all the disquiet in Republican ranks on what Trump means for the GOP and the country, Trump must grapple with a serious primary challenger. Because LBJ (Gene McCarthy), Ford (Reagan), Carter (Ted Kennedy), and the 41st himself (Pat Buchanan) did not survive theirs. The unchallenged – Reagan, Clinton, Bush 43, Obama – all enjoyed re-election.