Tony Blinken, a former national security official and current senior adviser to Democratic frontrunner Joe Biden’s campaign, weighed in on the political firestorm over President Donald Trump’s efforts to pressure Ukraine into manufacturing political dirt on Democratic frontrunner Joe Biden on Wednesday.

Shortly after the White House released its version of the phone call between Trump and Ukraine President Volodymyr Zelensky, Blinken — who served as the deputy national security adviser in the Obama administration — said on MSNBC that he found the memo describing the call “concerning” and “worse than we feared.”

“First, we have confirmation that the President of the United States, using the full power of his office sought from a leader of a foreign country to dig up discredited dirt on his leading political rival, in this case Joe Biden,” Blinken said, adding that Trump also sought to bring in other members of his administration, such as Attorney General Bill Barr. A DOJ spokesperson said Wednesday that the attorney general was not involved in the effort.

Blinken argued that the scandal is “corrupting [Trump’s] entire administration in the pursuit of his own personal political gain” due to how “Ukrainians desperately need assistance from the United States.”

“When the President and the Ukrainian president are talking about the relative lack of assistance from other countries, that only underscores how important the United States is to Ukraine,” Blinken said. “So implicit in this, if not explicit, is the President saying, gee, it would be a shame if something happened to that assistance you need that you get mostly from the United States.”

Watch Blinken’s reaction below: