After more than 30 years in the United States Senate and nearly 20 years after his first try for his party’s Presidential nomination, Joseph Biden has no doubts about making another run for the White House. “I’m in,” the Delaware Democrat said Friday as he began a five-day visit to the first-in-the-nation primary state. “I know I’m supposed to hedge, but I’m in.” Biden dropped out of the 1988 nomination race amid allegations of plagiarism. He then suffered a cerebral aneurysm virtually on the eve of the New Hampshire primary. He recalls being given a 30 percent chance of surviving....