Peter Blanchard is the State Department liaison for the event at the Russian Embassy that Chance needs to crash in "Embassy Row". He is understandably suspicious of the under-identified "Mr. C.C. Baxter" who turns up uninvited, but when the Secretary of Defense vouches for him personally, he backs off rapidly.
When "C.C." and Emma Barnes are picked up by Alexei Volkov, the embassy's head of security, and accused of spying, Blanchard comes to check they are not being mistreated. This is, however, a ruse, as Blanchard turns out to be the high-level spy, Raven, that everyone is looking for, and murders Volkov whilst trying to frame the other two Americans. The Russian lives long enough to avenge his own death, and save our heroes, by putting two rounds in the spy, and Emma and Chance flee the scene.