WILLIAMSBURG, Va. — Vice President Joseph Biden, soon to be Germany-bound for his first foreign trip in his new gig, stopped by the House Democratic retreat Friday morning to tell lawmakers what they already know: They stand on the front lines of crises posing historic challenges at home and abroad. In a characteristically loose but sober speech, Biden braced Members for tough decisions as leaders grope for a path toward economic recovery and international stability. “We don’t have much of a road map to go by,” he said. Biden suggested the “constellation of crises” facing policymakers also presents great opportunities, but leaders will need to thread a needle to avoid disaster. “If we do everything right, we do it with absolute certainty, there’s still a 30 percent chance we’re going to get it wrong,” he said. Biden, the former Senator who most recently led the Foreign Relations Committee, decried what he called a squandered opportunity by President George W. Bush in the wake of the 9/11 attacks to wean the nation off foreign oil and bring the international community together to combat terrorism. The speech was billed as a foreign policy update, but Biden opened with more than 17 minutes on domestic troubles. Abroad, he said the “good news” is that the world has embraced President Barack Obama as a figure who represents “the totality of American values.” Biden said American forces have made real progress in Iraq, estimating the United States to be at “the 20-yard line, moving in” although there remains “an awful lot to be done” toward political reconciliation. In Afghanistan, by contrast, Biden said “the road remains incredibly perilous,” placing the American mission there “closer to being on our 20-yard line with 80 yards to go.”