muslims special i.d. cards listing their religion and potentially creating a database to track all muslims living in the u.s. [ inaudible ] >> there should be a lot of systems beyond databases. we should have a lot of systems. today, you can do it. but right now, we have to have a border. we have to have strength, we have to have a wall, and we cannot let what's happening to this country happen. >> reporter: the gop front-runner today tweeting he didn't suggest a database, but still not dismissing the idea as some of trump's rivals have done. >> we don't need division in america. we need to be united. >> you talk about closing mosques, you talk about registering people, that's just wrong. >> reporter: even ted krouz, in a rare break with trump -- >> the first amendment protects religious liberty and i've spent