Republicans are accusing Democrats of invoking Nazis after Vice President Biden sent out a fundraising message warning of the looming "GOP blitzkrieg" of dirty campaign tactics.

The e-mail was sent via the Democratic Congressional Campaign Committee. In it, Biden warned that House Democrats would "be hit with a GOP blitzkrieg of vicious Swift-Boat-style attack ads, Karl Rove-inspired knockout tactics, thinly veiled attempts at character assassination and Tea Party disruptions."

Republicans took exception at the characterization, given that "blitzkrieg" was a term to describe Germany's military offensives during World War II. A spokesman for House Minority Leader John Boehner told The New York Daily News that "invoking the Nazis' crimes against humanity in a political debate is simply inappropriate."

Invoking Nazism and the Holocaust has become a common rhetorical war-fighting tactic since last summer's health care debate. But while the word blitzkrieg, which literally means "lightning war," was used to describe the Germans' lethal combination of tanks, troops and fighter planes during World War II, it has since become anglicized. The shortened form of the word, blitz, is commonly used in sports and other settings to describe any intense campaign or attack.