CQ Politics: Key House Democrats released details of their proposed climate-change legislation Tuesday but left unresolved what could be the most controversial issue: how to distribute emission allowances under a cap-and-trade program to address global warming. House Energy and Commerce Committee Chairman Henry A. Waxman , D-Calif., released the bill with Edward J. Markey , D-Mass., who leads the subcommittee on energy and environment. They are hoping to mark up the legislation by the end of …