For all the talk in certain Western diplomatic circles about finding an “off-ramp” for President Putin as a means to curtail the Russian strongman’s trail of destruction across Ukraine, what could be more effective than a throwing down of the gauntlet from the White House? That question just became slightly less hypothetical thanks to the customarily cunning Russian foreign minister, Sergey Lavrov, who told Rossiya-1 television that Moscow would consider a meeting between President Biden and Mr. Putin on the sidelines of the G20 summit “if a proposal is received.”