What exactly would Trump's Triumphal Arch commemorate?

If completed as planned, Donald Trump's triumphal arch outside Arlington National Cemetery will tower over the graceful Memorial Bridge, obstruct the view of the Lincoln Memorial from the cemetery (and vice versa), and offend anyone whose taste is north of Liberace. But there's another aspect of this grotesquerie that deserves some attention: Namely, what is the triumph Trump is celebrating? The Arch of Titus in Rome celebrates the Roman victory over the Jews and the sacking of Jerusalem in…