Canada ? Security issues highlighted the North American summit Monday where President Bush and the leaders of Mexico and Canada are crafting a plan to secure their borders in case of a terrorist strike or other emergency.

Bush, Mexican President Felipe Calderon and Canadian Prime Minister Stephen Harper want to find a way to protect citizens in an emergency – perhaps an outbreak of avian flu or a natural disaster – without the tie-ups that slowed commerce after the Sept. 11 attacks.

Calderon is cutting short his trip to Canada to return home to manage his own natural disaster: Hurricane Dean is bearing down on the Yucatan Peninsula. Maurico Guerrero, a spokesman for the Mexican embassy in Canada, said Calderon will attend all the events today at the summit, but his schedule has been streamlined and he will no longer stay another day, as planned.