OTTAWA - Critics on the left say it's a plot to undermine environmental, health and labour standards, while those on the right complain it costs too much and erodes national sovereignty.

The reality is that the Security and Prosperity Partnership among Canada, the United States and Mexico has so far been more about political tinkering than anything else.

"It's largely an assemblage of bureaucratic initiatives to harmonize cross-border trade,'' says Fen Hampson, an international relations expert at Carleton University in Ottawa.

"SPP was somebody's bright idea to pull it all together and put a nice red bow around the box. Is it driven by some grand, strategic vision? Absolutely not.''

Much of the criticism springs from the fact the work is done mostly behind closed doors by an array of working groups, task forces and advisory panels. In many cases, however, the mountain has laboured to bring forth a mouse.

A case in point was a much-ballyhooed pilot project to speed customs clearance for commercial traffic on the heavily travelled Peace Bridge between southern Ontario and northern New York.

It was supposed to be a model for the rest of the Canada-U.S. border, ensuring trade would flow unimpeded while would-be terrorists would be snared in the security net. But despite backing from business interests on both sides of the border it hit a roadblock in April, when U.S. federal officials pulled out after two years of talks.

Nor has the SPP helped to smooth over the feathers ruffled in the tourist trade by an American demand that everyone crossing the Canadian border by land produce a passport. That one is now on hold until at least the summer of 2008 while officials search for alternative ID -- perhaps a modified, security-enhanced driver's licence -- to substitute for passports.

The same difficulty in sorting out conflicting national objectives has been evident on other fronts.

Canadian officials, for example, have found the U.S. and Mexico hesitant to move on common standards for food labelling, inspection and safety. The sticking point is that current Canadian rules are often more stringent than those in the other two countries.

The current summit at Montebello, Que., is expected to produce, at best, an agreement for all three countries to recognize each other's scientific research on food and drug products, in the hope of reducing duplication in the regulatory process.

Similarly, the national leaders are expected to sign on in principle to a new protocol for border security in times of crisis, such as terrorist attack or flu pandemic. But most likely they won't have a final deal -- just a directive to yet another team of bureaucrats to work out details.

It's a far cry from the glitz that surrounded the announcement of the SPP at a similar summit in 2005. The aim then was supposed to be unprecedented economic integration.

Some analysts even spoke of an eventual customs union accompanied by a North American security perimeter, as recommended by a blue-ribbon task force of politicians and corporate heavy-hitters from the three countries.

The practical result was a proliferation of working groups that have haggled over everything from food additives to automobile standards, rules for dangerous goods containers, steel industry strategy and continental energy security.

The enduring problem is translating the statements issued by the national leaders into concrete steps by others.

"You can have nicely worded commitments to say we need to do this or that,'' says Hampson. "But at the end of the day regulators and legislators have to act.''