Bush joins Canadian Prime Minister Stephen Harper and Mexican President Felipe Calderon on Monday in Montebello, Quebec, in hopes of expanding cooperation among their countries, which enjoy the largest trading partnership in the world.

The two-day North American Leaders’ Summit appears to lack a signature issue, except perhaps a new U.S. push to halt Mexico’s bloody drug wars.

Instead, the broad theme is economic prosperity, built around several topics: border security, competitiveness with India and China, product safety and energy solutions.

Underlying those points are technical but important matters, such as aligning bordercrossing procedures and commercial standards.

“It’s not necessarily sexy stuff, but it’s essential to our security. It has to be done,” said Roger Noriega, Bush’s former assistant secretary of state for Western Hemisphere affairs. “And it just so happens that Mexico and Canada have renewed themselves with the election of two right-of-center leaders who see the world a lot like Bush does.”

The setting will be at a massive red-cedar chateau on the banks of the Ottawa River. Some nettlesome issues await the leaders.

Bush promised to deliver an overhaul of U.S.-Mexico immigration policy, and now he will be seeing Calderon for the first time since that effort collapsed in Congress. Calderon has made clear he is after more from the U.S. than hundreds of miles of fencing to keep the countries divided.

Harper is frustrated over a U.S. law that tightened passport rules for Canadians visiting the United States, although Bush has little influence over the matter.

The leaders probably will discuss how best to counter the message of Venezuela’s fiery president, Hugo Chavez, who is leading a leftward shift in Latin America. Each has a strategic interest in promoting democracy in the Western Hemisphere, an area of emphasis for Bush before he leaves office in January 2009.

“What’s really important is that they continue to reflect the significance of North American integration — the fact that there are post 9/11 problems, but they aren’t going to undermine trade and investment,” said Charles Doran, a scholar at John Hopkins University’s School of Advanced International Studies.

Doran foresees no dominating issue at the summit. “That’s a good thing. There’s not one thing that’s going to preoccupy them,” he said.

The meeting comes as the U.S. government is poised to offer a major aid plan to Mexico to fight drug trafficking and violence. Bush may announce part or all of the proposal during the summit if the details are completed in time. The effort is expected to help pay for equipment and training.

Calderon has cracked down on drug traffickers and sent soldiers into violence-plagued areas since he won election last year. The effort has earned praise from Bush. Still, many people in Mexico are wary of U.S. intervention, fearing it could threaten their sovereignty. That is a common worry in cross-border efforts.

“I think (Calderon) understands that he can’t — and he shouldn’t have to — take these guys on all by himself,” said Noriega, now a visiting fellow at the American Enterprise Institute. “And I think President Bush realizes that whether Calderon succeeds or fails will have a dramatic effect on our security.”