Walker, who recently toured the southern border with Texas Gov. Greg Abbott, said that as president he would first secure the border, then "go on to enforce the laws we already have."
A pair of U.S. House and Senate committees are holding a joint field hearing on allegations of narcotic overprescribing practices and retaliatory behavior.
Walker’s proposal, from September 1999, would have set up a regional primary system for picking each political party’s presidential nominee, rotating states into and out of early positions.