SNEAK PEEK: Megyn Kelly Sits Down with Donald Trump

North Rips Obama Over Low Army Levels: 'He Failed National Security 101'

As Donald Trump moves closer to becoming the official Republican nominee, he has begun the process of considering his running mates.

Trump said he's narrowed the choices down to five or six experienced politicians, but he won't announce a decision until the Republican National Convention in Cleveland.

Campaign Manager Corey Lewandowski is heading up the vetting effort, along with former candidate Dr. Ben Carson and others.

Tonight on Hannity, Lewandowski weighed in on that process, saying his job was to make sure their team "recommends somebody good to Mr. Trump."

He said the most important criteria in any potential candidate is that they'd be effective at continuing Trump's agenda should something happen to the president and who "understands the legislative process intimately."

"(We want to) make sure that in the first 100 days--which are so critical--we get done the agenda which Mr. Trump is putting forward, which is cutting taxes, reducing our deficit, renegotiating our trade deals."

He said that it's not a matter of selecting someone of the right gender or geographic representation.

"It's who's best as a partner to bring our country from where it is, because we have to make sure that we don't allow another 4 or 8 years of a Democrat in the White House who's taking our country in the exact opposite direction. So, it's more important about making sure we have the right person on the ticket to make sure Mr. Trump gets his agenda done."

Earlier on The Factor, Trump confirmed a report that he's narrowed his shortlist to five "excellent" people and is not ruling out Chris Christie.

He said he has "envisioned" the announcement being made at the GOP convention, which is July 18-21 in Cleveland.

Trump: Best Way to Protect Sanctity of Life Is to Vote for Me

EXIT POLL: Almost Half of Sanders Voters in WV Say They'd Vote Trump in General

Here's What Judge Nap Believes Is the 'Secret to Trump's Success'