AP (Erik Schelzig) reports:

Republican Rep. Marsha Blackburn’s Senate campaign announcement ad has been blocked by Twitter over a statement the abortion rights opponent makes about the sale of fetal tissue for medical research.

Blackburn, who is running for the seat being opened by the retirement of Tennessee Sen. Bob Corker, boasts in the ad that she “stopped the sale of baby body parts.” A Twitter representative told the candidate’s vendors on Monday that the statement was “deemed an inflammatory statement that is likely to evoke a strong negative reaction[."]

Twitter said the Blackburn campaign would be allowed to run the rest of the video if the flagged statement is omitted. While the decision keeps Blackburn from paying to promote the video on Twitter, it doesn’t keep it from being linked from YouTube and other platforms.

Twitter advertising policies indeed forbid “Inflammatory or provocative content which is likely to evoke a strong negative reaction,” though it’s hard to see what political ads these days wouldn’t “evoke a strong negative reaction” or be seen as “inflammatory or provocative” by some.

Twitter, it seems to me, is as constitutionally entitled to pick and choose which advertising it runs as are newspapers (including back when newspapers were more important than they were now, and when many cities had only one major daily newspaper easily available). Over-the-air TV and radio broadcasting, see Becker v. FCC (D.C. Cir. 1996) are generally barred from selectively excluding ads by political candidates — but those rules stem from the longstanding treatment of such broadcasters as less protected by the First Amendment; Internet site operators, such as Twitter, have the same First Amendment rights as newspapers and other fully protected media, and that would include the right to choose what not to publish.

Nonetheless, how users should react to private company decisions such as this is an interesting and important question; and it will also be interesting to see how Twitter applies its policy to other political ads.

Disclosure: I have argued, in a paper commissioned by Google, that search engine results are protected by the First Amendment; see also Zhang v. Baidu.com Inc. (S.D.N.Y. 2014), which takes that view. But the First Amendment analysis here doesn’t rely on the argument in that paper; the right of a content provider to refuse to publish political advertising that it doesn’t want to publish is pretty straightforwardly recognized.

UPDATE: Twitter has reversed course on this:

Our ads policies strive to balance protecting our users from potentially distressing content while allowing our advertisers to communicate their messages. Nowhere is this more difficult than in the realm of political advertising and the highly charged issues that are often addressed therein. After further review, we have made the decision to allow the content in question from Rep. Blackburn’s campaign ad to be promoted on our ads platform,” a spokesperson said in a statement….

While we initially determined that a small portion of the video used potentially inflammatory language, after reconsidering the ad in the context of the entire message, we believe that there is room to refine our policies around these issues.