Dear President Trump and the Republican Party of the United States,
Canada is a federation of 10 provinces, each with sovereignty equal to, if not greater than, the states in your Union, whose sovereignty and rights you are such great champions of.
Therefore Canada would not become the 51st state. It would become the 51st, 52nd, 53rd, 54th, 55th, 56th, 57th, 58th, 59th and 60th states. Each with two senators and a proportional number of representatives in Congress.
Your kind offer of joining your Union has been accepted. Please prepare accommodations for 20 new senators and dozens of new representatives, and kindly inform Senator John Thune and Congressman Mike Johnson there will be new elections for Senate majority leader and Speaker of the House.
Please do not worry about security for the new senators and representatives, which will be provided by units of Joint Task Force 2 that will be arriving shortly in the DC Metro area.
*Note that the common measure of "economic success" is GDP, which does not include public sector or exports. As a result the country with the smallest public sector per captia and the least amount of exports looks significantly better than it actually is.