Last week, U.S. President Barack Obama formally extended an invitation to Canada to join the Trans Pacific Partnership negotiations, a proposed trade deal that includes the U.S., Australia, Brunei, Chile, Malaysia, New Zealand, Peru, Singapore, and Vietnam (Mexico was also added last week). Supporters have lauded the TPP as potentially the world’s most important trade pact and the Canadian government spent months crossing the globe to lobby for an invitation.

Yet dig beneath the heady promises and the benefits for Canada are hard to identify. The price of admission was very steep – Canada appears to have agreed to conditions that grant it second-tier status – and the economic benefits from improved access to TPP economies are likely to be relatively minor since we already have free-trade agreements with four of the ten participants.

Given those conditions, why aggressively pursue entry into the negotiations? The reason stems less from gaining barrier-free access to a handful of relatively small economies and far more about using the TPP as a backdoor mechanism to promote regulatory changes in Canada.

Given Canada’s late entry into the TPP process, the U.S. was able to extract two onerous conditions that Prime Minister Stephen Harper downplayed as the “accession process.” First, Canada will not be able to reopen any chapters where agreement has already been reached among the current nine TPP partners. This means Canada has already agreed to be bound by TPP terms without having had any input. Since the TPP remains secret, the government can’t even tell us what has been agreed upon.

Second, Canada has second-tier status in the negotiations as the U.S. has stipulated that Canada will not have “veto authority” over any chapter. This means that should the other nine countries agree on terms, Canada would be required to accept them.