Is extreme vetting Trump's invisible wall?

President Trump promised to tighten US borders by restricting travel and building his big beautiful wall between America and Mexico. But legal challenges to his travel ban and Mexico's refusal to foot the construction bill are making it hard for him to deliver. Nevertheless, the administration is moving forward on both fronts. It's opened a $600 million bidding contest for construction on the border wall and, in the past two weeks the administration implemented a new policy of "extreme vetting" of visa applicants -- one of Trump's signature campaign promises, but without the fanfare. This vetting was revealed in a series of diplomatic cables sent by Secretary of State Rex Tillerson to embassies and consulates, explaining the new policy.