Barack Obama will later address both houses of Congress on an issue that could define his presidency: healthcare.He warmed up with a speech to school children in Virginia on Tuesday, encouraging them to work hard in class. While even that appearance drew accusations from many conservatives that he was trying to indoctrinate children with his socialist ideas, the healthcare debate has been much more emotive. Obama’s critics say his plans for healthcare are unclear and the fiercest among them have seized on this to portray his reforms in sinister terms. Carroll Doherty of the Pew Research Center believes the president’s task now is to clarify his vision: “People have raised issues like “death panels” which are not in the bill and so there’s been a lot of confusion in the public’s mind about this. It’s a very complicated issue…it’s very complex and so he needs to cut through a lot of that complexity and set out what he really wants out of Congress,” Carroll said. More than 46 million Americans have no health insurance and Obama has made fixing this his domestic priority. His Republican opponents hope it could be his “Waterloo.” Obama’s will speak to Congress at 02:00 CET on Thursday morning. His message could be critical to the health of his presidency.