Early this year, New York's MTA voted to ban "political" advertising from the city's bus and subway system. The vote was meant to let MTA officials reject contentious material like anti-Islam ads without getting embroiled in legal challenges, but it also raised a lot of strange questions about what exactly constitutes political speech. The latest iteration of this: how political (and appropriate) is advertising a TV show with Nazi symbols?

As PIX11 News producer Katherine Lam and others note on Twitter, Amazon is currently running an MTA promotion for its alternate history series The Man in the High Castle — a show in which 1960s America is occupied by Nazi Germany and Imperial Japan. Accordingly, Amazon papered the seats with American flags based on Japan's Rising Sun design and a modified version of the Nazi Parteiadler, its swastika replaced by a somewhat less fraught Iron Cross. The results drew consternation from some riders, as well as Anti-Defamation League regional director Evan Bernstein, who described Amazon's campaign as exploitative.

42nd St shuttle to #TimesSquare covered in Nazi Germany and Imperial Japan symbols for @amazon ad. Is this ok? pic.twitter.com/ysJ3m0UIPT — Katherine Lam (@byKatherineLam) November 23, 2015

If you consider fascist imagery political — which it would almost certainly be, in certain contexts — Amazon is stepping into slightly muddy waters here. After instituting its ban, the MTA rejected bank ads that promoted raising the minimum wage, and it refused to run promotions for a comedy documentary called The Muslims are Coming, which parodied earlier anti-Muslim advertisements.

But a judge overruled the second decision last month, calling it "utterly unreasonable." Her ruling points out that the MTA did run a series of obviously political statements for the series Mr. Robot, making the line even harder to draw. Like Mr. Robot, The Man in the High Castle is promoting a fictional series with in-world political material, and an MTA spokesperson confirmed to The Verge that the ad "does not run afoul" of its standards — and that "under the First Amendment, we as a public entity are required to post the ads." So for now, the most important boundaries are those of Amazon's good taste.