Backers of a new initiative to end the federal prohibition on marijuana made the case that a "silenced majority" of Americans are "beginning to rise up" to express their support for ending what they say has been a failed war on marijuana. The organizations -- Law Enforcement Against Prohibition, Students for Sensible Drug Policy, and FireDogLake -- are circulating a petition online and on college campuses asking President Obama to end the federal ban on using the drug.