Hillary Clinton's most senior advisers are in a state of "panic" about her presidential prospects and are plotting to enlist Democrat leaders in Congress to thwart her rival Barack Obama's ambitions. The Clinton camp is braced for Mr Obama to win a series of primary elections over the next three weeks, which they fear could hand the Illinois senator unstoppable momentum in the race for the White House. Mr Obama has begun calling those "super delegates" - 795 congressmen and senior party officials who could break a dead heat - who are committed to Mrs Clinton, asking them to change...