Donald Trump has been running for president on building a wall between the U.S. and Mexico to better secure the border, but during Ronald Reagan's presidency, another approach was pondered, former Oklahoma Gov. Frank Keating said Tuesday.
"In my past, I've supervised a big chunk of the federal law enforcement establishment. The Immigration Services [and] Border Patrol reported to me during the late Reagan period. And we were even contemplating [at the time] a ditch, not a wall ... because we have to take control of our borders," Keating told CNBC's "Squawk Box."
In the late 1980s, Keating served as assistant secretary of the Treasury, where he presided over agencies including what were then called the Customs Service and the Immigration and Naturalization Service.
Like Trump, Reagan also waded into immigration, signing the Immigration Reform and Control Act, which aimed to tighten border security and crack down on companies that knowingly hire illegal immigrants. But the 1986 law also provided amnesty for 2.7 million undocumented immigrants.
Keating said Tuesday that securing the U.S. borders is especially important considering the threat of terrorism, and an open border policy is not sound policy. "We've been debating this since the 1986 Immigration Reform Act. We really haven't done anything about it."
Appearing on CNBC from the Republican National Convention in Cleveland, Keating said he plans to vote for Trump, though the real estate mogul wasn't even close to his first choice.
"My twin brother gave me a visa to come over. My twin brother [Dan Keating] is the chairman of the Trump campaign in Oklahoma. I went through a whole bunch of other candidates," said the ex-Oklahoma governor, who started off supporting former Florida Gov. Jeb Bush and then Wisconsin Gov. Scott Walker.
"I voted in the Oklahoma primary for [Ohio Gov.] John Kasich. But [now] Trump's our guy," Frank Keating continued. "I think as this convention evolves and unfolds there will be more and more people that will have a higher comfort level for [Trump]."
Kasich is certainly not among the Trump converts. Citing the presumptive GOP nominee's rhetoric and policies, the Ohio governor said he won't be attending the convention being held in his state's second-largest city, Cleveland.
"The host governor, you should show up," Keating said. "I'd give eye, teeth to have this thing in Tulsa City or Oklahoma. But that never happened."
Like Kasich, Wall Street may also be wary of Trump, after campaign manager Paul Manafort said on Monday the GOP wants to revive the Glass-Steagall Act.
Keating, formerly CEO of the American Bankers Association, said: "There should be a debate on the subject of Glass-Steagall [on whether] to erect a higher wall or to remove the wall entirely."
Critics argue the 1999 repeal of the Depression-era law, which kept investment and commercial banking separate, gave rise to the 2008 financial crisis and the too-big-to-fail bailouts.
The Dodd-Frank Wall Street Reform and Consumer Protection Act, which was born in the aftermath of the financial crisis and puts major regulations on the financial industry, has its critics, too.
Keating said one thing is for sure: "We can't tread water" on the issue.