Washington (CNN) Secretary of State Rex Tillerson defended himself Sunday from criticism leveled at him by Sen. John McCain.

The Republican senator wrote in a New York Times op-ed earlier this month that Tillerson's warning against "conditioning our foreign policy too heavily on values" told oppressed people the world over that the US would not help them if doing so comes in conflict with moves to benefit US interests.

Tillerson said in an interview that aired Sunday on NBC's "Meet the Press" that the Arizona lawmaker was well within his rights to criticize him and listed what he viewed as the US values that "can never change."

"America's values of freedom, of treatment of people, of human dignity, of freedom of expression throughout the world, those are our values," the former ExxonMobil CEO said.

But Tillerson reiterated his belief that those values should not determine foreign policy.

"I make a distinction between values and policy," Tillerson said. "Policy has to be tailored to the individual situation."

He said successful foreign policy, which should be "adaptable," would lead to the spread of those values.

In the interview, Tillerson also discussed a visit from Russian Foreign Minister Sergey Lavrov last week and defended not discussing Russian attempts to influence the 2016 election during that meeting.

The secretary of state said it was one of many issues that undermined trust between the two countries and that Russia's role was "well documented" and not in question. He said the US could not simply look past the issue, and that problems were baked into the US-Russia relationship.

"We're not trying to start with a clean slate," Tillerson said. "You cannot erase the past."