Reuters — A rare burst of good news on President Barack Obama's health care program has given Democrats their first glimmer of hope in months on an issue that has helped drag the party down ahead of November's U.S. congressional elections.

A better-than-expected enrollment of 7.1 million people in health care exchanges under "Obamacare" gives Democrats a positive argument to counter relentless Republican calls to repeal the law, and could help them change the topic to the bread-and-butter economic and job issues Democrats prefer to talk about.

Democrats still face a tough challenge to improve public views of the law, particularly in conservative states where endangered senators like Mary Landrieu of Louisiana and Mark Pryor of Arkansas could face a steep political price at the polls for their support of Obamacare.