White House senior adviser Stephen Miller defended President Trump's tweet calling for a boycott of Goodyear after an employee at a plant in Topeka, Kan., said the company's corporate office listed “Make America Great Again” hats as an “unacceptable” accessory for employees in the workplace.

"Don't buy GOODYEAR TIRES—They announced a BAN ON MAGA HATS. Get better tires for far less!” Trump tweeted Wednesday.

TRUMP CALLS FOR GOODYEAR BOYCOTT AFTER REPORTED BAN ON MAGA HATS

"To that tweet, I say amen," Miller told FOX Business Network's Maria Bartiromo in a Thursday interview. "It's time for traditional Americans to stand up for their values, stand up for their beliefs, and not be bullied by the radical left."

The controversy began this week after the Goodyear employee shared a slide that he said came from the company's corporate office in Akron, Ohio. The slide, reported by WIBW, showed two categories: "Acceptable" and "Unacceptable."

Under "Acceptable" were Black Lives Matter (BLM) and Lesbian, Gay, Bisexual, Transgender Pride (LGBT).

WHITE HOUSE URGES GOODYEAR TO 'CLARIFY THEIR POLICY,' CALLS BLUE LIVES MATTER AN 'EQUITY ISSUE'

Under "Unacceptable" were Blue Lives Matter, All Lives Matter, MAGA and politically affiliated slogans or material.

"This notion that you can go to a workplace in America and express support for radical Marxist movements, express support for anti-police movements, and you can't express support for Donald Trump or the police and law enforcement? The left is trying to create a two-tiered system of free speech in this country," Miller said. "A system where leftist thought is completely protected, sacrosanct, can't criticize it, but if you express traditional, mainstream American views like 'I love cops,' that somehow is hate speech and you should be punished."

CLICK HERE TO GET THE FOX NEWS APP

White House Press Secretary Kayleigh McEnany urged Goodyear to “clarify their policy.”

The company said in a statement Wednesday that it supports "both equality and law enforcement" and that  “the visual in question was not created or distributed by Goodyear corporate, nor was it part of a diversity training class.”

Fox News' Brooke Singman contributed to this report.