Sean Trende’s excellent Real Clear Politics article on the missing white voters in 2012 got me thinking: In what states did Mitt Romney get fewer votes than George W. Bush had in 2004 and in what states did he get more? In both these elections incumbent presidents won with 51% of the popular vote. Roughly equal numbers of Americans voted — 122 million in 2004, 129 million in 2012 — and similar numbers of votes were cast for Bush (62.0 million) and Romney (60.9 million), which means that Romney got 2.4% fewer votes than Bush.

When you put the percentage increases or decreases on an outline map of the states, you get a pretty clear picture. Romney received fewer votes than Bush in the Northeast, the Midwest and the Pacific states, and he received more votes than Bush in the South and the Rocky Mountain states. But let’s look at the numbers in a little more detail.

In the Northeast, Romney received fewer votes than Bush in every state except Massachusetts, his home state and that of Bush’s 2004 opponent John Kerry (where he got 11% more votes) and the fast-growing District of Columbia (+1%). He trailed far behind Bush in Vermont (-24%), New York (-16%), New Jersey (-11%) and Maine (-11%). New York and New Jersey have had considerable domestic outmigration, and it’s likely that Republican voters are leaving in disproportionate numbers; turnout in these states was also depressed by Hurricane Sandy. Vermont and Maine are states with very low population growth.

In the Midwest, Romney received fewer votes than Bush in every state except Missouri (+2%). The declines were largest in Illinois (-9%), which like New York and New Jersey has had heavy domestic outmigration; Michigan (-9%), which lost population during that period; and South Dakota (-9%), where turnout was unusually high in 2004 due to the high-stakes Senate race in which John Thune beat sometime Senate Majority Leader Tom Daschle.

Among the Pacific states, the greatest decline in Republican votes between 2004 and 2012 came in Barack Obama’s boyhood home of Hawaii (-38%); also, Bush’s percentage in 2004 was helped by Hawaii’s tendency, apparent in elections ever since it achieved statehood, to give unusually heavy support to incumbent presidents of both parties. Republican turnout was also way down in California (-12%), which has had plenty of domestic outmigration; Oregon (-13%); and Alaska (-14%).

In the South, Romney received more votes than Bush in every state except Oklahoma (-7%), where the Republican decline was similar to that in neighboring Plains states Kansas (-6%) and Nebraska (-7%); and West Virginia (-1%), where Barack Obama in 2012 received 27% fewer votes than John Kerry. Romney made big gains over Bush in North Carolina (+16%), a target state in 2008 and 2012 but not 2004, which had the biggest percentage gain in total turnout of any state between 2004 and 2008; South Carolina (+14%) and Arkansas (13%). But Romney got only 6% more votes than Bush in 2008 and 2012 target state Virginia and only 5% more in 2000-12 target state Florida. Romney even got more votes than Bush in Bush’s own Texas (+1%), but of course it is one of the fastest-growing states.

In the Rocky Mountain states, Romney got more votes than Bush in every state but New Mexico (-11%). Romney made big gains over Bush in Nevada (+11%) and Arizona (+12%), which were the two fastest-growing states until the housing crash, in heavily Mormon Utah (+12%) and target state Colorado (+8%).