Mayor Bill de Blasio keeps Police Commissioner William Bratton with him in the spotlight these days to serve as his sorely needed bridge to the NYPD. The last time Bratton was commissioner here, Mayor Rudy Giuliani rather famously pushed him out of that spotlight.
Beyond this role reversal, a more important one is taking place, hidden in plain sight: de Blasio's most spirited detractors are coming from a corner of organized labor.
In Wisconsin, Republican Gov. Scott Walker -- now mulling a presidential run -- won widespread admiration from the political right in 2011 when he curtailed the powers of his state's public employee unions.
Membership in public-service unions had by then surpassed that of private-sector unions nationally. Labor activists generally found their political allies among Democrats and progressives, who tried to recall Walker.
But here's the New York City Patrolmen's Benevolent Association, its president, Patrick Lynch, and smaller police unions all voicing the loudest condemnations to date of an avowedly progressive mayor.
Of course, law-enforcement unions are different from other labor organizations. They represent civilian employees inside quasi-military structures. And of course, cops do not generally bargain in solidarity with musicians, teachers or social workers. Much to the PBA's irritation, United Federation of Teachers president Michael Mulgrew joined a rally over the death of Eric Garner.
Just the same, it now becomes a Democratic City Hall's turn to worry about the workforce of a department, in this case the NYPD, deferring to its appointed managers.
The politics of public employees questioning authority seem to vary depending on which employees do the questioning and when.
Don't expect Republicans in Albany, or the Cuomo administration, to take off after the PBA. Upcoming Senate hearings are due to focus on protecting officers, and may also address reforms aimed at individual cases of police abuse.
The PBA is not alone in clashing with de Blasio. City Hall has also run afoul of the Correction Officers Benevolent Association over changes in the Rikers Island jails.
Nor did the PBA suddenly become aggressive with de Blasio's election, or his embrace of Rev. Al Sharpton or his remarks on the Garner case.
In 1992 came a famously unruly PBA protest against Mayor David Dinkins near City Hall. In 1997, the PBA urged Giuliani to refrain from attending funerals of cops killed in the line of duty. In 2004, PBA delegates voted to demand Ray Kelly step down as police commissioner.
Having pro-union props doesn't seem to help de Blasio with the PBA.
His first year as mayor saw a near-constant succession of police flashpoints -- from appointment of a police inspector general to his defense of the Michael Brown and Eric Garner shooting protests.
In contrast de Blasio's relationships with the real-estate and business communities, some of whose leaders openly fretted in 2013 about the loss of Michael Bloomberg in City Hall, seem remarkably cordial.
The city has seen racial and municipal-labor issues combined in a single crisis, perhaps the biggest of which culminated in a crippling two-month strike in 1968 -- that time, by the teachers.