Supporters of decriminalizing marijuana are hoping to build momentum on Capitol Hill after a historic election that saw the politics of pot take center stage in four states. Forty-six percent of Americans support legalizing marijuana, a new high, according to a survey conducted by Gallup in October. The trend has shifted upward in recent decades while opposition to such a move has declined. For medical marijuana use, the support is even higher. Seventy percent of Americans said they favored making marijuana for medicinal purposes legally available.