A crucial senate race is heating up in the US state of Massachusetts.<br /><br />Republican candidate, Scott Brown, is threatening to overturn a Democratic stronghold for nearly 50 years.<br /><br />If Brown beats rival Martha Coakley, it could jeopardise the healthcare reform bill being pushed by Barack Obama, the US president.<br /><br />Al Jazeera's Rosiland Jordan explains. (19 Jan, 10)
