. >>> let's bring in constitutional law expert robert shapiro. he's also a former clerk for retired supreme court justice john paul stevens. good afternoon to you, sir. >> good afternoon. >> as more states legalize same-sex marriage, is there going to be more pressure on the justices to address this issue? >> absolutely. i think the justices inevitably react to the trends that they see around. and as more and more states do it, this issue of what is going to be the federal treatment of state declarations of same-sex marriage is inevitably going to a rise. and that's why i think it is likely that the supreme court will address the challenges to the defense of marriage act to really decide that issue about whether the federal government can have its own definition of marriage or whether it will have to defer to the state's definition of marriage with regard to this issue as it usually does with regard to other aspects of marriage. >> if the high court takes up doma, if they decide on doma, if we get a decision sometime in the summer, what will that