WASHINGTON - Attempting to rouse a party shaken by electoral setbacks, President Obama told fellow Democrats yesterday he would press ahead with his health-care proposal and other pieces of his ambitious agenda, rejecting suggestions a more cautious approach might minimize losses in the upcoming midterm elections.

Obama, who left the White House during a blizzard, sought to rally Democratic National Committee members in a speech that was part pep talk and part prescription for what the party must do to overcome problems culminating in the loss of the Massachusetts Senate seat held by the late Democratic icon, Edward M. Kennedy.