Colorado Democrat Mark Udall issued a statement late Thursday afternoon calling for CIA Director John Brennan to resign after his claim in March that the CIA had not improperly searched the computers used by Senate staffers turned out to be wrong.

“I have no choice but to call for the resignation of CIA Director John Brennan. The CIA unconstitutionally spied on Congress by hacking into Senate Intelligence Committee computers,” Udall said in the statement. “This grave misconduct not only is illegal, but it violates the U.S. Constitution’s requirement of separation of powers... The CIA needs to acknowledge its wrongdoing and correct the public record in a timely, forthright manner—and that simply hasn’t occurred under John Brennan’s leadership.”

Brennan, who previously served as Obama’s counterterrorism adviser, vigorously denied a report in March that the CIA had searched computers used by staffers of the Senate Intelligence Committee and intentionally made congressional oversight of the agency difficult. These claims were first aired in a fiery floor speech by Sen. Dianne Feinstein (D-CA), who chairs the committee. However, Brennan recanted Thursday after a report by the CIA’s inspector general showed that Feinstein’s claims were accurate.

Udall’s statement is noteworthy in particular because he is fighting one of the most competitive Senate races this year. The first-term senator is neck-and-neck with Rep. Cory Gardner in a campaign that may determine control of the Senate in 2015. While the Rocky Mountain State’s electorate is certainly more libertarian-leaning than the mean and Udall has long been a vocal civil libertarian, it’s still noteworthy that a candidate in a swing state is taking such a firm stance on this issue. It shows the sea change in American political attitudes around surveillance and the general conduct of the war on terror over the past decade as both parties have become more dovish and more skeptical of the intelligence community.

The nonpartisan Cook Political Report has currently classified the Colorado Senate race as a tossup.