Speaking on Newsnight, Pence indicated that the US and its European allies would be compelled to "confront [Russian President Vladimir Putin] militarily" if Russia expanded its war efforts.
He described the US role as a "backstop" in confronting aggression, with European allies expected to be at the forefront.
Pence praised the "coalition of the willing" for formulating security guarantees that he believes would create conditions for a lasting peace and have captured Putin's attention.