Quantifying the domestic political impact of having Canada as the 51st state of the USA
It is often neither easy nor worthwhile to quantify dumb, but there are exceptions, and my inner data nerd saw a fairly straight path to doing so here.
The President of the United States has recently made great fun of saying that Canada should join the United States as the 51st State. While clearly just juvenile smack talk, and further evidence of how embarrassingly low the political bar is in America, it is possible to quantify the impact this could have on domestic US politics if it came to pass.
Political Impact
Canada would be the largest state in the union in terms of population (Canada’s 41 million exceeds California’s 39m, Texas’s 29m, Florida’s 21m, and New York’s 20m) and size (9% larger than the entire United States today). It would be the third largest economy (Canada’s US$2.2 trillion [GDP 2022] is smaller than California’s $3.6tr and Texas’s $2.4tr, but larger than New York’s $2tr or Florida’s $1.4tr).
Under the “Equal Footing Doctrine,” new states must be admitted on equal terms with the original states. Congress may not impose conditions on a state’s admission that would diminish its sovereignty and jurisdiction. Politically, this means two Senators in the upper house and Congressmen/women (oops, is mentioning women too DEI?) in the lower house in proportion to its population. This would make Canada the most politically powerful state in the union.
Senate
Canada would have two Senators, assuredly Democrats in the current political environment. This would expand the Senate to 102 seats, requiring 52 seats for a bare majority, or 51 seats plus the tie-breaking vote of the Vice-President. Applying this change (+ 2 Democrats) from today back to the year 2000, the addition of 2 Democrat Senators from Canada would not have changed the Senate majority party. However, it would have strengthened several narrow Democrat majorities and forced 2 Republican majorities to rely on the Vice-Presidential vote to pass straight majority bills (if the Senate is deadlocked the Vice-President casts the deciding vote), in addition to getting all of their members in line. Impactful when things are tight, but not game-changing.
House of Representatives
It is a different story in the House of Representatives. Adding 12% to the population, along with their likely voting preferences, would shift the balance of power significantly. Unlike the Senate, the size of the House of Representatives has been capped at 435 members since 1911 (when the US population was 93 million and there were only 46 states). It has been assumed that this would remain the case. Using the same methodology as the US Census Bureau to determine the division of seats in the House of Representatives, Canada would receive 47 seats (2024). Because the size of the House is capped, these seats are taken from other state delegations as they have a smaller proportion of the total population (a “reapportionment” that already occurs after every decennial census). 33 states would lose seats, most just 1, but Michigan, Illinois, Pennsylvania, and Florida would lose 2, Texas and New York would lose 3, and California 7.
Given that Canuckistan is famously liberal-democratic (“socialist” to the ignorant, and “communist” to the even more ignorant) it can reasonably be assumed that the bulk of these 47 seats would go to Democrats. A realistic ratio might be a 5:1 Democratic advantage, meaning 39 Democrats and 8 Republicans in 2025 (there are only a few regions of Canada that could conceivably muster a Republican majority – I’m looking at you Southern Alberta, interior BC and rural Saskatchewan but your populations are not large). There is no magic way to work out the overall impact of these 47 new Canadian House members replacing 47 existing members of both parties. However, calculating the ratio of Republicans and Democrats in each state delegation, applying these ratios to the seats lost and totalling them for all 50 states to generate expected wins and losses, and then adding the new members from Canada, is not a bad way to go. It shows a net gain to the Democrats of 13-16 seats going back to the year 2000 or, in political terms, a swing of 26-32 seats. In a country with only two represented parties – the bare minimum required for a democracy – where even "independents" caucus with one of the parties, politics is a teeter-totter, when one party goes up the other goes down.
Looking at Republican-led Congresses since the year 2000, 6 of the 10 Republican majorities in the House of Representatives since 2000 would have been reversed if Canada was the 51st state, including the current one 2025-2027 (4 cleanly changing hands giving Democrats double digit majorities, and 2 on the bubble). The current 119th Congress would swing from a Republican majority of 220 to 215 Democrats (assuming current vacancies stay with the same party), to a Democratic majority of 229 seats to 206 Republicans (details below).
Electoral College – Presidential Selection
Those who follow US politics know that we do not directly elect the President or Vice-President. Instead, an ad hoc body called the Electoral College decides for us. It is currently comprised of 538 members (“electors”) appointed by the states and allocated according to a formula (one for each Senator and member of the House of Representatives, with Washington DC also getting 3 even though they have neither Senators nor Representatives). All states but two have a winner-take-all-system that awards all Electoral College votes to the winner of the popular vote, although not all states compel electors to vote for the popular vote winner, and not all states have penalties for electors who defy the voters (“faithless electors”). The whole thing is an anachronistic mess, but this is what we have underpinning the world’s greatest democracy.
If Canada was a state today it would receive 49 Electoral College votes according to the current formula, but the body would presumably grow by only 2 (to account for Canada’s Senators) as the balance of Canada’s votes would come from states losing electors. Recalibrating the 2024 electoral college vote to reflect Canada’s input (assumed to be for the Democratic candidate) would have reduced the margin of victory but not changed the outcome (312-226 to 289-251). However, if Canada had been part of the Union in 2004, its (then 44) votes would have swung the results of the election from a Republican win (George W. Bush) to a Democratic one (say hello to President Kerry!). In fact, there would never have been a President George W. Bush in the first place as Canada’s presence in 2000 would have swung the election to the Democrats (and President Gore!). So, pulling Canada in would have the potential to move the dial significantly toward the Democrats in tight elections.
Conclusions
What have we learned from this, other than my inner data nerd has too much time on its hands?
Only what everyone intuitively understands:
Not only are POTUS’s comments regarding Canada joining the union incredibly childish, but it would be just the thing to Make the Democratic Party Great Again and just the opposite for the Republicans. And this from a Republican President.
So, now we know just how dumb dumb is. Anybody surprised?
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Methodology
This is a hypothetical situation and there is no perfectly objective way to analyse it, and I am no data scientist, but this methodology uses long-established processes in the American political system, logical methods, and conservative assumptions where required. Think of it as highly-advanced “back of the envelope” calculations.
Approach:
1. Apply the same “method of equal proportions” methodology as the US Census Bureau to determine the division of seats in the House of Representatives with Canada added as the 51st state:
a. Determine the number of seats in the House for each state, including Canada
b. Calculate which states lose seats to make way for Canada
c. Calculate expected seat losses by Democrats and Republicans to make way for Canada using the composition of state House delegations as a starting point.
2. Look deep into the crystal ball (and population numbers) to guesstimate the number of Democrats and Republicans expected to be elected in the new “state” of Canada.
3. Calculate the expected net win/loss for the Democratic and Republican parties with Canada added and recalibrate the majorities for a sample of Congresses back to the year 2000 (results show a consistent gain to the Democrats of between 13-16 seats).
4. Conduct a similar analysis for the Electoral College Presidential selection.
Key Assumptions:
1. The House of Representatives remains capped at 435 seats (as it has been since 1911), with each state guaranteed at least one member, with the rest “apportioned” by the same formula in use since 1941, the “method of equal proportions”. (If the House were expanded to absorb Canada, but still using an equal proportions method, the impact would almost certainly be slightly greater in the Democrat’s favor.)
2. The best way to calculate expected seat losses in the House by Democrats and Republicans is to employ an averaging calculation across all states losing seats: 1) calculate the percentage split in House delegations; 2) multiply this percentage by the seats lost; 3) total for all states losing seats to come up with expected losses per party. Obviously, this method both ignores the gerrymandering that occurs at the state level (states control district boundaries and state governments often try to make things work out for their party) and calculates partial seat losses, something that is not possible in the real world. However, pulling the calculation across all 50 states should cancel many of these anomalies, so we are going with it, faute de mieux.
3. Canada naturally leans heavily Democrat. The estimate of Republican versus Democrat representatives in the new Canadian House delegation assumes that the more liberal overall tilt to Canadian politics puts the Democrats at a significant advantage while examining the population of areas that could potentially lean Republican. It is assumed here to be a 5:1 Democratic advantage (a ratio considered generous to the Republicans).
4. The Electoral College continues to function as it does today.
Calculating Apportionment of Seats in the House of Representatives
Quoting directly from the Census Bureau:
“Mathematically speaking, the goal of the Method of Equal Proportions is to minimize the relative (or percentage) differences in representation (the number of people per representative) among the states.
In practice, we use this method to determine the number of seats each state receives by:
1. Calculating a set of “priority values” for each state, based on the state’s apportionment population.
2. Sorting those values from largest to smallest.
3. Allocating a seat to a state each time one of its priority values is included in the largest 385 values in the list
We calculate the priority values by dividing the state’s apportionment population by the geometric mean of its theoretical current and next seats. The formula for calculating priority values is as follows: V=P/√n(n-1), with V representing a priority value, P representing a state’s apportionment population, and n representing the number of seats a state would have if it gained a seat.” (US Census Bureau)
Calculating Win/Loss in the House of Representatives by Including Canada (2025 example)
Calculating Impact on House of Representatives Back to 2000
