Fox News host Chris Wallace in a Sunday discussion challenged White House aide Stephen Miller about the need for a wall on the southern U.S. border.

In an interview on Fox News Sunday, Wallace pointed out that 80-90 percent of cocaine, heroin, and fentanyl are seized as U.S. ports of entry.

Miller complained that President George W. Bush failed to protect American citizens against immigrants crossing the border illegally.

"Four times as many people were coming across the border in 2000 as [compared to] now," Wallace noted. "So why is that a national emergency?"

"I can go down to the details as much as you want to," Miller replied.

"But please don't," Wallace replied.

"You cannot conceive of a nation without a strong, secure border," Miller opined. "It is essential to sovereignty and national survival to have control over who does and who doesn't enter the country."

"There's been a huge increase in drug deaths since George W. Bush and Barack Obama were president," the White House adviser added.

"But 80 to 90 percent of those drugs don't come across in unfenced areas," Wallace interrupted. "They come across from ports of entry. Those are your own Customs and Border Patrol numbers."

"Which is why we also asked for additional resources at the ports of entry," Miller replied.

"Which you got [in the recent DHS bill signed by Trump]," Wallace observed.

Miller, however, suggested that the U.S. needed screeners "at that same density across every inch and mile of the southern border."

"You don't know what you don't know," he continued. "You don't catch what you don't catch... This is defending our own country!"

"I question whether or not that's, in fact, the case," Wallace quipped.

At the conclusion of their talk, Wallace acknowledge that it had been difficult to counter all Miller's talking points.

"It's always a challenge interviewing you," Wallace remarked.