Suppressive Fire
One element of military tactics is suppressive fire, the launching of a barrage of missiles at the enemy to force him to take cover. The reasoning being that an enemy hunkered down is not able to do much else. The attacker can then proceed with his advance. Having air supremacy usually constitutes effective suppressive fire.
Politically, the left has relied on suppressive fire to emasculate its opponents. The favored missiles are accusations of racism or bigotry rained on anyone tempted to oppose the left’s agenda. As a result the general public is presented with a predominantly leftist political landscape.
Until fairly recently, this tactic has been successful, especially on the minds of elected Republicans. But the Tea Parties have led to the rank and file overcoming their fears, and the left’s suppressive fire is no longer effective. Consequently, elected Republicans, and especially those recently elected under the Tea Party’s shield, are also showing more courage. Apparently, the left needs a new missile.