learn how you can help at amazonwatch.org. >> brennan: that's it for us today.or watching. but before we go, we want to thank the jones day law firm and everyone behind the scenes at "face the nation". they have been working nonstop getting us moved in up here. until next week, for "face the nation", i am margaret brennan. captioning sponsored by cbs captioned by media access group at wgbh access.wgbh.org >>> danger in the middle east. iran denies a u.s. charge that it's behind attacks in the world's largest oil refinery. >> we're not going to stand for that. >> whether the iranians directly engaged in this is yet to be seen. >> is a price fight at the pump? >>> on strike, why thousands of gm workers are trading assembly lines for picket lines. >>> courthouses open for migrants in limbo as the border crisis shifts south. >>> medicare fraud, a cbs news investigation exposes a new scheme to rip off taxpayers and track down the doctors