One of the more controversial commemorative half dollars of the classic-era series was certainly the 1936 Cincinnati Music Center 50th Anniversary half dollar.
Bills calling for the coin were introduced in the House Senate (January 15, 1936) and (January 16, 1936). The Senate bill sought coins "in commemoration of the fiftieth anniversary of Cincinnati, Ohio, as a center of music, and its contribution to the art of music for the past fifty years." The Senate bill was ultimately passed in both chambers of Congress, and was signed into law by President Franklin Delano Roosevelt on March 31, 1936.
Critics quickly questioned the claim of Cincinnati being a center of music for 50 years (i.e., since 1886) and would later question the use of a portrait of Stephen Foster on the coin's obverse. (See the links below for more on these aspects of the coin.)
I think at least some of the controversy surrounding the coin could have been avoided if the House version of the bill was the one that progressed to the finish line vs. the Senate's bill. The House bill called for coins "in commemoration of the Fiftieth (Golden) Anniversary of Cincinnati, Ohio, as a center of music, and its contribution of
the annual May Festival to the art of music for the past fifty years." (Emphasis added.) The included reference to the city's May Festival allows such an overall statement of purpose to align reasonably well with confirmed history.
The annual May Festival (a choral music festival) is known around the world and has played host to acclaimed US and international musicians and conductors. The Festival was launched in 1873 to "transform the musical tastes of America and, at the same time, enhance Cincinnati's image and national reputation." (www.mayfestival.com) If a coin bill that included language regarding Cincinnati's May Festival had advanced, I can Imagine folks being a bit more accepting of the coin's back story. The dates (i.e., 1873 vs. 1886) would still not have been a perfect match, but an internationally-acclaimed music festival linked to Cleveland for 50+ years would have given respectable credence to the "center of music" claim.
The House bill was introduced by Representative William Emil Hess (R-OH) and was referred to the House Committee on Coinage, Weights, and Measures. The Committee reported the bill favorably, and recommended that it pass, though it did specify several amendments: the total mintage for the coin was to be raised from 15.000 to 25,000 and the specifications of the mintage amount for individual Mint facilities (Philadelphia - 10,000, Denver - 2,000 and San Francisco - 3,000) were to be deleted (but no restrictions were to be placed on which facilities could strike the coins).
After its return from Committee, the House bill was Laid on the Table in favor of the Senate bill, which was passed by the House without issue. The Senate bill did not include a reference to Cincinnati's May Festival, and specified a mintage of just 15,000 coins. Unfortunately, as written, the Senate bill became law and triggered a long-standing controversy. Ah, the benefits of 20/20 hindsight!
1936 Cincinnati Music Center 50th Anniversary Half Dollar

For more on the history of the Cincinnati half dollar, see:
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1936 Cincinnati Music Center 50th Anniversary-
1936 Cincinnati Music Center 50th Anniversary - Revisited-
1936 Cincinnati Music Center 50th Anniversary - Ephemera-
1936 Cincinnati Music Center 50th Anniversary - Mintage Requests-
What If? 1937 Cincinnati Music Center 50th AnniversaryFor other of my posts about commemorative coins and medals, see:
Commems Collection.