Threats by members of the Los Angeles City Council to use the city’s pension funds to penalize investors if they sell the Los Angeles Times to Charles and David Koch could be illegal and unconstitutional, experts say.A proposal by councilman Bill Rosendahl would allow the city to yank investments by the city’s three pension funds in the Tribune Co., which owns the Times, if the company opts to sell the paper to someone who does not uphold “the highest terms of professional and objective journalism.”Rumors that libertarian industrialists Charles and David Koch might buy the paper spurred him to propose...