From NBC's Mark Murray
Sometimes you have to work a bit harder when you're not a presidential front-runner. Want evidence? Just take this weekend, when Biden, Dodd, and Richardson will be speaking on Saturday morning at the New Hampshire Democratic Party state convention; then they'll fly to the Hawkeye State to address an Iowa Democratic Party dinner later that evening; and then they'll fly back to New Hampshire to participate in Sunday's debate. Whew.
By comparison, Clinton, Edwards, and Obama won't be attending the New Hampshire convention (they'll be sending surrogates instead), and Obama is skipping the Iowa dinner.