The longstanding debate over the political versus judicial safeguards of federalism has paid insufficient attention to the role presidential politics might play in promoting state policy-making autonomy. In certain circumstances, the President may be better positioned than either the courts or Congress to be politically sensitive to state policy initiatives and to create the flexibilities in federal law necessary to accommodate them. A powerful example of this dynamic is presented by the problem of state marijuana legalization. A sharp policy conflict has arisen between the federal Controlled Substances Act, which purports to impose a zero-tolerance regime on marijuana distribution and use, and state laws permitting distribution and use of marijuana for medical and, more recently, recreational purposes. While the courts and Congress have played virtually no role in permitting such state policy experiments to go forward, the Obama administration's low key approach toward enforcing the CSA's marijuana ban in marijuana legalization states has created space for state level policy experiments. The article argues that the Obama administration's position reflects political sensitivity to the policy preferences of a small number of marijuana legalization states that play an outsized role in presidential "electoral math." The marijuana legalization example provides strong evidence that presidential politics can be a significant political safeguard of federalism where a grouping of "swing states" has a salient policy preference that is inconsistent with a well-supported national policy alternative in an era of close presidential elections.