Back in the days after the 2012 election, when it became clear that despite losing the popular House vote, Republicans had actually won a sizeable majority in the House, plenty of speculation set in as to why: Was it gerrymandering? Was it geography? Or just luck? Thanks to data from the latest edition of Vital Statistics on Congress (a joint product of the Brookings Institution and the American Enterprise Institute that has just been posted online), we can put 2012 in better historical context. Last year marked the first time since at least 1946 (the first year for which Vital Statistics has data) that one party (the Democrats) won the pluralirty of the popular vote in U.S. House but ended up with less than the majority of seats. While such a reversal of electoral fortune is unusual, a significant disparity between a party’s seat share and vote share is not. Historically, Democrats have benefited from distortions of apportionment much more than Republicans, especially during the 1960s and 1970s.