Mark Carney is not abandoning CUSMA. But Donald Trump’s ego demands 'wins,' and Carney has promised to sign a deal only if it is 'good for Canada.' So Canada must be prepared to walk away if Trump’s demands would make us the 51st state in all but name. The immediate result would be costly, with a recession, affecting everything from the job market to the Canadian dollar. Much will depend on how well we are proceeding with Carney’s efforts for 'strategic autonomy' and the options generated. But it can be managed.