crimea. . the u.s. is denying a visa request for iran s pick to be its next u.n. ambassador. the white house says it opposes the appointment of abu at that lebby because of the 1979 takeover in iran. elizabeth prann is live in washington with this story. elizabeth? reporter: hi, patty ann. tehran refuse to say back down on its nomination for ambassador to the united nations. the white house is saying no, they will not issue a visa, congress taking it one step further, both the house and the senate passing a bill unanimously, prohibiting the ambassador from entering the united states. senator ted cruz, a sponsor, is encouraging president obama to send a strong message of intolerance towards terrorism. i think that s a real moment of clarity and i appreciate the republicans and the democrats who worked with me to pass this legislation and i appreciate the president doing the right thing and barring this acknowledged
this swiss cheese approach. reporter: he says this proposal left him skeptical and concerned. obviously, we can t be granting exemptions in general because the whole point is to clamp down on trade and investment. you will only consider any exemption if it was in the service of a larger good. reporter: the white house aides say they want legislation that ultimately changes iranian behavior. critics say allowing exemptions would take the teeth out of the sanctions and ultimately prove that the iranians allow the iranians to continue nuclear development. bret: mike emanuel live at the pentagon. thanks. texas republican senator john cornyn asked secretary of state hillary clinton to deny a visa request from iranian leader mahmoud ahmadinejad to come to the u.s. for next week s non-proliferation meeting at the united nations. mothers of three american hikers detained in iran are asking president ahmadinejad to bring them home if he comes to the u.s.