Poll: Join Missile Shield?

U.S. President George W. Bush caught Canadian officials off guard on Wednesday in calling openly for joint action on a continental missile defense shield.

Bush made clear his desire for Canada's support in setting up an anti-missile system in Alaska to protect western North America, a politically sensitive issue that Canadian officials said before his visit was unlikely to be raised.

Bush, paying his first official visit to Canada, encouraged Ottawa to sign on during private talks with Liberal Prime Minister Paul Martin on Tuesday, officials said.

The proposed system, which has become a political minefield for Canada's minority Liberal government and main Conservative opposition, is a land-based shield designed to shoot down missiles from so-called rogue states like North Korea.