Sen. Ron Johnson Ronald (Ron) Harold JohnsonThe Hill's Morning Report - Sponsored by Facebook - Trump previews SCOTUS nominee as 'totally brilliant' The Hill's 12:30 Report: Ginsburg lies in repose CHC leaders urge Senate to oppose Chad Wolf nomination MORE (R-Wis.) said Sunday he doesn't have an issue with President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE revoking ex-CIA Director John Brennan John Owen BrennanJournalism or partisanship? The media's mistakes of 2016 continue in 2020 Comey on Clinton tweet: 'I regret only being involved in the 2016 election' Ex-CIA Director Brennan questioned for 8 hours in Durham review of Russia probe MORE's security clearance, but added that the practice shouldn't become "routine."

Johnson said on "Fox News Sunday" that he's not sure there is evidence Brennan improperly shared classified information, but said that he "misused his privilege."

"I don’t want to see this become routine. I don’t want to see this become politicized," Johnson added.

In addition to revoking Brennan's clearance, Trump put out a list of several former intelligence officials from whom he's considering taking clearances away. Nearly all of those individuals have been vocally critical of Trump.

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"The best way of handling this is if you don’t have confidence in former CIA officials or government officials that you’re not going to be consulting with, just don’t gain them access," Johnson said. "You gain access when you have a need to know. If you’re not going to be consulted you don’t have a need to know."

"So again, I don’t want this becoming routine," he continued. "But again John Brennan really did cross the line. He’s one of the leaders of the resistance movement. I understand why President Trump is pretty frustrated."

On President Trump pulling more clearances, @SenRonJohnson tells Chris: I don’t want this to become routine, but John Brennan really did cross the line. pic.twitter.com/Bdx5ZloG1p — FoxNewsSunday (@FoxNewsSunday) August 19, 2018

The White House justified revoking Brennan’s clearance last week by saying the former CIA head has made unfounded allegations against the current administration, and claimed he has lied during congressional testimony in the past.

Skeptics have noted Brennan is among the most outspoken critics of the Trump administration, frequently lashing out at the president on Twitter. He called Trump's performance at a meeting with Russian President Vladimir Putin last month "treasonous."

Dozens of ex-intelligence officials have expressed support for Brennan in recent days and condemned Trump’s decision to revoke his clearance.