Mayors Against Illegal Guns -- a group organized last year by the mayors of New York and Boston -- said it plans to run television ads, starting with the Sunday morning political shows, seeking repeal of the "Tiahrt Amendment." In the advertisement, Chaska, Minn., Police Chief Scott Knight describes how the Tiahrt Amendment "prevents him from being able to effectively address gun crime," a new release said. The amendment (actually, a series of riders to appropriations bills funding the Bureau of Alcohol, Tobacco, Firearms and Explosives) is named after its sponsor, Rep. Todd Tiahrt (R-Kan.). The measure restricts cities' access...