What does "up to" of " it's also up to Congress" mean?

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Speaking on NBC's "Meet the Press," Brennan said he's been contacted by a number of lawyers about the possibility of an injunction in the wake of Trump's move to revoke his clearance and threaten nine others who have been critical of the president or are connected to the Russia probe.

"If my clearances and my reputation as I'm being pulled through the mud now, if that's the price we're going to pay to prevent Donald Trump from doing this against other people, to me it's a small price to pay," Brennan said. "So I am going to do whatever I can personally to try to prevent these abuses in the future. And if it means going to court, I will do that."

Brennan, who served in President Barack Obama's administration, said that while he'll fight on behalf of his former CIA colleagues, it's also up to Congress to put aside politics and step in. "This is the time that your country is going to rely on you, not to do what is best for your party but what is best for the country," he said.