and mr. verrilli said that really the constitution itself contains structural limits on this power. treaties have to be ratified by the senate, implemented by congress. and those are the bodies that are going to protect state rights to ensure a treaty doesn't upset the balance in the constitution. >> ifill: the justices sounded a little desperate? >> yes. in fact, at one point mr. verrilli was give an hypothetical that he said was unimaginable and justice kennedy interjected and said "it's unimaginable that will you brought this prosecution." >> ifill: (laughs) marcia coyle, thanks for being here. >> my pleasure, gwen. >> ifill: late yesterday, in a rare bipartisan step, the senate moved toward approving a law banning discrimination against gay workers. as public opinion has continued to shift on gays in the military and same-sex marriage, seven republicans joined with democrats yesterday to advance the employment non- discrimination act. jeffrey brown has more. >> it's now time to pass a national law! >> brown: supporters of the bill, including democrat ben cardin of maryland, pres