President Joe Biden did not make a mistake when he described Russian President Vladimir Putin as a killer, a top adviser said Monday. “President Biden was asked a direct question. He gave a direct answer. That’s how he has operated for 40-plus years in public service, and it’s how he’ll continue to operate as president,” national security adviser Jake Sullivan said during an appearance on MSNBC. Earlier this month, Biden was asked during an interview with ABC host George Stephanopoulos, who used to be an aide in former Democrat President Bill Clinton’s administration, whether he agreed that Putin was a “killer.” “Yes, I do,” Biden responded. Biden also vowed that Putin would “pay a price” for allegedly interfering in the 2020 election. Putin responded by challenging his counterpart to a live debate, but the White House dismissed the challenge. The Russian Foreign Ministry said Monday that it regretted the Biden administration did …