INDIANAPOLIS – Former Indiana Senator Dan Coats is speaking publicly for the first time since his resignation as director of national intelligence. But while he addressed the whistle-blower controversy which originated in his final days on the job, he didn’t have much to add.

Coats kept a long-scheduled date to address the Economic Club of Indiana in Indianapolis, hours before House Speaker Nancy Pelosi announced an impeachment inquiry centering on President Trump’s attempt to pressure Ukraine into investigating former Vice President Joe Biden. A still-unnamed whistle-blower filed a complaint with the intelligence community inspector general, who ruled the complaint “serious” and “urgent” — a finding that’s supposed to send the complaint to Congress. The administration’s refusal to forward the complaint is also a focus of the impeachment inquiry.

Coats says he didn’t know the whistle-blower complaint was working through the system. The inspector general’s three-day review period ended August 15, Coats’ last day as intelligence director. Coats says the complaint reached the desk of his acting successor the next day.

Coats didn’t comment further on the Ukraine controversy, and little on his tenure in the administration. He says the nation is facing “difficult times,” without elaborating, and says he believes in the constitutional framework set up by the Founding Fathers.

During a brief audience Q-and-A, Coats did, after a four-second pause, part ways with Trump over the president’s insistence on a border wall. Coats says there are some spots along the border where a wall would be an effective way to stop immigrants from trying to slip into the U-S illegally. But he says border agents over the years have found hundreds of tunnels, some of them equipped with railroad tracks and stretching a mile away from the border on either side. He says half-jokingly that he’s concluded a 20-foot wall would simply be met by “a 21-foot ladder.”

Coats says the U-S faces a lengthy list of global hot-spots with the potential to cause security concerns, from Afghanistan to Africa and from Venezuela to North Korea, all made more challenging by technological advances. But he warns an increasingly neglected security challenge is one at home: a still-ballooning national debt in the trillions of dollars. As the debt and deficit grow, he warns it’ll be harder for the U-S to meet security needs around the globe.