Housing is strangely expensive in California and New York.  Economists routinely blame their unusually strict regulation of land use and construction.  Political observers, in turn, routinely blame unusually strict regulation on NIMBYism – current residents’ “Not In My BackYard” mentality.  Strict regulation of construction is so entrenched that only recently has the opposing view even found a name.  YIMBY – Yes in My BackYard – is finally a thing.

But how on Earth can YIMBY gain political traction – especially in the big, liberal, high-rent states of California and New York?  Publicizing astronomical economic benefits seems unlikely to make converts, especially when leftists can demagogue against deregulation and greedy developers.  To animate liberal Californians and New Yorkers, you probably need to somehow connect the high cost of housing to their hated enemies, the Republicans.  Given Republicans’ marginal role in Sacramento and Albany, this seems like a tall order.

But wait.  Remember how Hillary Clinton won the popular vote, but lost the election?  The reason, of course, is that she won by huge margins in states like… California (30 points) and New York (22 points).  For Democrats, these margins are probably counter-productive in the short-run, and clearly counter-productive in the long-run.

In the short-run: If more of the nation’s Republicans lived in CA and NY, Clinton might have won big swing states like Wisconsin, Michigan, or Pennsylvania – without endangering her hold on CA or NY.

In the long-run: If more people – of any party! – from solidly Republican states moved to CA and NY, Democrats could count on more electoral votes.

The short-run partisan effect, admittedly, is debatable.  Perhaps the Pennsylvanians most likely to move to New York and Michiganders most likely to move to California are disproportionately Democratic.  The long-run effect, however, is clear.  If CA and NY sharply increased their population, the states would remain solidly Democratic but sharply increase their electoral vote tally.  Since electoral votes are zero-sum – five more for CA and NY means five less for the rest of the country – this is even better for Democrats than it sounds.

Going forward, then, here’s how I’d sell YIMBY to California and New York.

1. We need more electoral votes to beat the Republicans.

2. The only way to get those votes is to to grow our population.

3. The only way to do that is to build a ton of new housing.

4. YIMBY!

What about Republican migrants ruining liberal enclaves?  That’s when you harp on the Democrats’ enormous margins.  In fact, given current patterns, CA and NY Democrats should actively hope for mass Republican migration.  Imagine turning CA into the west-coast version of Florida, drawing in millions of Republican retirees with cheap housing.  Every Republican who moves to CA or NY enhances Democratic power in America.

Couldn’t Republican states use exactly the same strategy?  Yes, but far less effectively.  The states with big Republican margins of victory already have pretty cheap housing and pretty light housing regulation.  But sure, there’s always room for a little more YIMBY.

Liberal states are vocally resisting Donald Trump, but it’s unclear that they’re hurting his re-election prospects, much less paving the way for a less Republican future.  YIMBY policies could conceivably tip the scales against Trump even in 2020, and would plausibly devastate Republicans in the long-run.  And since almost all housing regulation is state and local, California and New York can start the great liberal YIMBY conspiracy today.