Popular name for the Nazi Party's Sturmabteilung, the SA or "stormtroopers." So called because their uniforms were brown. Nowadays, the label (often used interchangeably with "blackshirts") generally applies to any group that exhibits blind loyalty to a leader, especially one that uses ugly tactics to support him or her.
The German brownshirts were formed (copied from a similar corps in Italy) in 1921 as the first formal gang of Nazi thugs. Their official purpose was to provide security at Nazi events: Germany was in a state of profound political ferment, still in shambles from World War I and the ruinous Treaty of Versailles, with communists and fascists fighting it out in the street to lead the populist movement.
Before long, the brownshirts were marching in street demonstrations, roughing up voters, and causing havoc whenever it suited Adolf Hitler's purposes. For years, they engaged in the kind of provocation of which the Reichstag Fire was symbolic: Hitler rode to power partly on a promise of restoring order in Germany, when his own hooligans were responsible for wrecking it.
After the Beer Hall Putsch of 1923, the brownshirts -- like the rest of the Nazi Party -- were thrown into disarray. They only got their act together again two years later. In 1931, Hitler put Ernst Rohm in charge of them, and he proceeded to treat them like his own mercenary army: between 1931 and the time Hitler was appointed chancellor in 1933, there were more than two million of them.
That was 20 times the size of Germany's treaty-limited army.
The brownshirts attracted every kind of dreg Germany could produce: men cashiered from the kaiser's devastated army after the First World War, turned out of their jobs in Germany's crippled economy, released from prisons the state could no longer sustain.
No wonder they ran amok.
Rohm had the idea that the SA could displace Germany's regular army, something the country's military leaders and industrialists -- not all of whom were Nazi loyalists -- couldn't countenance. Hitler purged Rohm in the Night of the Long Knives in 1934.
That event marked a sudden decline in the brownshirts' power. With Hitler secure in power, street violence was no longer necessary: it was even counterproductive to the dictator's ends. The Nazis had the ordinary agents of the state to do the heavy lifting, and the elite SS for political tasks requiring force. Their numbers were dramatically reduced and the remainder were turned into "home-guard" militia.