On April 26, Attorney General Eric Holder sent a letter to Kansas Gov. Sam Brownback in response to a bill he signed into law, the "Second Amendment Protection Act", which would nullify federal gun control laws and criminalize any attempt by federal officials to enforce such laws in the state of Kansas. Holder implies in his letter that the 2nd Amendment is not absolute, and that Congress can regulate beyond its enumerated powers. He explicitly makes clear that he believes the Supremacy Clause allows federal law to always trump state law, regardless of whether it is Constitutional.
Here is the letter below:
To which Gov. Sam Brownback responded:
And Kansas Secretary of State Kris Kobach elaborated on the failings of Holder's interpretation of the Constitution:
(2nd page below)