Regarding my claim that Dukakis would have won in 2008, Andrew Gelman writes:
From our analysis of the Current Population Survey post-election supplement, here are our estimates for voter turnout in 2008: 76.4% white, 11.9% black, 7.4% hispanic, 4.3% other, with the categories defined as mutually exclusive (for example, if you're white and hispanic, you count as "hispanic"). The exit polls say 74% white, 13% black, 9% hispanic, and 5% other (not adding to 100% because of rounding error), but I think CPS is more trustworthy.
Now we can take the Dukakis numbers and plug them into the 2008 turnout numbers, as long as we make some estimate for the votes of "other." I'll assume 55%, halfway between his performance among whites and among hispanics. (By comparison, we estimate from the Pew pre-election polls that Obama got 45% of the two-party vote among whites, 96% among blacks, 68% among hispanics, and 59% among others.)
Plugging in Dukakis's percentages by ethnic group and using the turnout numbers of 2008, we get a national adjusted Dukakis vote of .40*76.4% + .89*11.9% + .70*7.4% + .55*4.3% = 48.7%, which is better than the 46.1% he actually received but not quite enough to win.
My counter argument is that even if Andrew's numbers are correct (they do contradict the exit polls, but those polls have a margin of error), then while my 50%+1 claim was slightly off, Dukakis still would have won an electoral college victory and become President.
According to Dave Leip's Atlas of Presidential Elections, Barack Obama received 52.87% of the national popular vote, and 365 electoral votes. Had there been an even, nationwide shift of 4.17% away from that total in all 50 states, and even if all 4.17% of those voters had shifted to McCain, it would not have flipped enough electoral votes to put McCain over the top. Only Florida (27), Indiana (11), Nebraska-02 (1), North Carolina (15), Ohio (20), and Virginia (13) were decided by 8.34% or less, flipping 87 electoral votes to John McCain. However, that would have still left our temporally-relocated Dukakis with 278 electoral votes, due to narrow victories in Colorado (8.95% minus 8.34% = 0.61%), Iowa (9.35% minus 8.34% = 1.01%), and New Hampshire (9.61% minus 8.34% = 1.27%). Further, even with 2012 reapportionment, in 2012 the "Dukakis" states would still have, in all likelihood, either 270 or 271 electoral votes, and still enoguh to win.
The one place were I would quibble with Andrew's numbers (which are extremely useful, especially the more specific turnout estimates), would be with his estimate on voting trends for "Asians" and "others." He puts this vote halfway between whites and Latinos, but that is a low-end estimate. In 2006, the Asian and "other" vote was halfway between whites and Latinos, but in in 2004, Asians and others were within 2% of Latinos, and 14% of whites. In 2008, according even to the numbers that Andrew sites, Asians and "others" are within 9% of Latinos, but 14% of whites. So, while it is possible that the Asian and "other" vote could be halfway between Latinos and whites, it is more likely that the Asian and "other" vote would be closer to Latinos. This would up an estimate of Dukakis's performance among Asians and "others" to something more like 60% (twice as close to Latinos as whites), thus adding another 0.25% to his total. Given current trends, and given that at least 1% of the country voting for third-parties in ten of the last eleven elections, that would lead to a Dukakis popular vote vitory in 2012.
(Then again, given that Bill Clinton lost the Asian-American vote twice, it is likely that Dukakis lost as well. However, to push this counterfactual to a truly absurd level, 2008 Dukakis would have benefited from the Asian-American backlash against neoconservative foreign policy, just as current Democrats have done. But, if I start making arguments like that, then I am straying from my original point.)
No matter what the specific amounts are (somewhere between a net of 6% and 8%), roughly half of the Democratic electoral improvement since the dark days of 1988 has come from demographic change, rather than from either infrastructure / strategy / activist improvements, or from poor Republican governing performance. Further, this demographic change is actually more problematic for Republicans than the other two areas, because it requires changing the coalitions rather then developing better infrastructure or simply hoping that Democrats can't get the economy going again. It is an underlying problem Republicans face, and which requires them to break out of the ongoing Nixon-McGovern framework of American political coalitions. From now on, the McGoverns are just going to keep winning, even if they were to nominate another Michael Dukakis.
Update: Ugh--how embarrassing. I orginally credited Nate Silver for this response, not Andrew Gelman. As someone who was mistaken for Jerome Armstrong for about two years, I know how annoying that can be. My apologies.