President Trump is backing away from threats to close the U.S.-Mexico border but a former federal immigration official says Trump certainly has that authority but other steps might make more sense.

Trump made the threat in response to the tide of illegal immigration and illicit drugs pouring into the U.S.  But after pleas from both Texas senators and Senate Majority Leader Mitch McConnell to keep the border open or risk massive economic repercussions, Trump says he will revisit the issue in a year and see if Mexico is living up to its responsibilities to interdict migrants and drugs.

But a former immigration official says Trump does have the authority to close the border.

"The president does seem to have extensive powers and other presidents have actually used those powers on various occasions to close the border," said Temple University School of Law Prof. Jan C. Ting, who served as assistant commissioner of the Immigration and Naturalization Service in the George H.W. Bush administration.

He says other presidents have closed the border, most recently George W. Bush for a brief time in the wake of the 9/11 attacks.

But while Trump could close the border, Ting says whether that's a good idea is another question.

"I don't think anyone has seriously questioned the ability of the president to exercise that power.  The only objection questions have been raised about the advisability of doing so and the economic consequences of doing so.

"Some of those arguments have been found persuasive by the administration, at least to the point of holding off immediate action," said Ting.

Ting says it's not clear if closing the border would achieve Trump's goals, although he believes it would put a lot more pressure on the Mexican government to cooperate with American efforts rather than playing a two-faced game of cooperating in certain situations while also facilitating the passage of Central American caravans to the U.S. border.

So what would be more effective?  Ting says Congress could make a huge difference by mandating all employers use -E-Verify to check the validity of the Social Security numbers used by prospective employees.  The practice is mandatory in Arizona but not nationwide.

He also says Trump's prized goal of a border wall would be effective.

"It's a force multiplier.  You can only afford to put so many border patrol agents on the border.  Having fencing up or a wall makes those agents more useful," said Ting.

Listen to the full podcast to hear more of Ting's analysis on closing the border and alternative methods of achieving greater control over the influx of people and drugs into the U.S.  Ting also explains why he believes President Obama greatly exacerbated the crisis at the border, and he details the remarkably swift evolution of Democrats from border hawks in the 1990's to most presidential candidates in the party today recoiling at the idea of stopping virtually anyone from coming into the U.S.