The Arms Export Act gives the President the authority to control imports and exports of anything deemed to be defense articles and defense services.
The State Department manages the US Munitions List.
http://www.pmddtc.state.gov/regulati..._official.html
If the State Department is blocking the import of Garands, it is doing so by direction of the President.
The BATF has a good site which explains who does what, and what hoops have to be jumped if you want to import defense articles into the US.
http://www.atf.gov/firearms/guides/i...dure-aeca.html