Turnout was painfully light Tuesday, because the main bout was a joke: Mayor de Blasio easily won the Democratic primary with more than 70 percent of the vote, even while pulling less than 10 percent more actual votes than he drew four years ago, when it meant just over 40 percent of the total ballots.

And his Tuesday share of the vote among Democrats, against utterly no-name opponents and with all the party’s special interests in his pocket, was a bit less than his general-election showing in 2013 — when Democrats were dead-set on winning after 20 years of Republican rule and after a barely-legal third term for Michael Bloomberg.

This was no vote of confidence, not when the mayor’s $5 million campaign war chest dwarfed his foes’ resources, nor when the unions he’d paid off with taxpayer dollars were dutifully in his camp.

He showed not a hint of shame in requesting and taking $2 million-plus in taxpayer funds for the primary, when his foes got nothing — and then going on vacation.

For all his claims to be transformational, for all his hopes for moral leadership of the national progressive movement, this is a triumph of incumbency in a system that gives incumbents huge advantages — a win for cynical and systematic exploitation of power.

If those same advantages, and NYC’s perverse campaign-finance laws, don’t choke off fund-raising for Nicole Malliotakis, the Republican he’ll face in the general election, then he’ll confront a bigger fight ahead — even though the Democrats’ vast edge in enrollment should by itself make her a longshot.

This is not a mayor who is loved, or even respected — just a guy who knows how to work the system, and even now is eyeing the next way to exploit it.