WASHINGTON (AP) — Former Virginia Sen. Jim Webb announced his presidential campaign on Thursday, opening a long-shot bid against Hillary Rodham Clinton and a field of Democratic rivals for the party's nomination.Webb, in an announcement posted on his campaign website, acknowledged he would face major hurdles but vowed to bring an outsider's voice to the 2016 race."I understand the odds, particularly in today's political climate, where fair debate is so often drowned out by huge sums of money.