At a fundraising event in Miami on Thursday night, President Obama told the audience that they needed to get Democrats to the polls in November because "in midterms we get clobbered." And recently, that's true — under certain conditions.

The Washington Post's Katie Zezima doesn't agree with that assessment. "[T]he president seems to forget the drubbings that Democrats have given Republicans in midterms past over the last 30 years," she writes, pointing to the midterms in 1982 and 1986, when the Democrats retook the Senate. And of course, 2006, when frustration with President Bush, the war in Iraq, and campaign contribution scandals gave the Dems the House.

Democrats have fared slightly worse than Republicans in midterm elections over the past century. Over that time period, Democrats have, on average, lost seats equivalent to 0.56 percent of the House in midterms — and gained 0.49 percent of the Senate. That's about two-and-half House seats lost and half a Senate seat gained with our 435- and 100-seat Congress (which has varied over the century).

But over the last century, politics shifted dramatically. The once reliably Democratic South became solidly red, thanks largely to the passage of the Civil Rights Act. If you take elections since 1970, Democrats fared worse: losing 0.13 percent of the House and 0.56 percent of the Senate. Still not a "clobbering," but not great.

Here's the thing, though. When you take into consideration who's in the White House, those numbers change dramatically. When a Republican is in the White House, Republicans have lost 6.87 percent of the House in midterms. When a Democrat is in the White House, Democrats have lost 7.99 percent of the House. But that's since 1910. Since 1970, Democrats have lost 7.3 percent of the House and 4.25 percent of the Senate in midterms with a Democratic president. For Republicans, the figures are about half as much in both cases.

This graph shows losses in the House (green) and Senate (yellow) by party of president, in the 11 midterms since 1970.

An important note: this is a very small sample size — only four midterm elections with a Democratic president since 1970. But the difference between how the party has fared in all midterms with how poorly it has done with a Democrat in the White House is striking.

All of that aside, we will make an admission. The best analysis of Obama's remarks comes from Slate, where Dave Weigel suggests that "Obama was dog-whistling past the graveyard," using the spectre of heavy losses in November — a very real threat — as a way of saying the party needs to counteract the decrease in the non-white vote since 2012. That's very true. But it doesn't hurt that Democrats really do get clobbered in midterms. When the president is a Democrat. Since 1970. Both of which happen to apply in 2014.