Every year Congress passes appropriations bills to authorize spending by federal agencies. Since 2003 Maurice Hinchey (D-NY-22) has introduced an amendment on the floor of the House of Representatives that would prohibit the Department of Justice from using federal funds to prevent 10 states, that have accepted medical cannabis use by referendum or legislative action, from authorizing the medical use of cannabis. Maryland, which recognizes medical cannabis use as an affirmative defense, would not be affected by the amendment. The amendment is co-sponsored by Dana Rohrabacher (R-CA-46), who along with Ron Paul (R-TX-14) and 16 other Republicans supported the amendment on libertarian and/or state's rights grounds. In 2006 the amendment received 163 votes. In addition to 18 Republican votes the 144 Democrats supporting the amendment were joined by Independent Bernie Sanders (VT-At Large). The House of Representatives has 435 voting members. This roll call vote (No. 333) was 163 votes for the amendment and 259 votes against it. Ten representatives did not vote, two seats were vacant, and the Speaker of the House does not vote.

Eleven states have medical cannabis legislation and twelve states have decriminalization laws. All together these 18 states have 169 representatives in the House. The Hinchey Amendment received the votes of 67% of the congressional delegations from states with medical cannabis legislation, the votes of 54% of the delegations from states with decriminalization laws, and overall the amendment received 57% of the votes of the delegations from these 18 reform states.

Congressional Quarterly provides assessments of the re-election prospects for members of the House of Representatives. The amendment received support from 75% of the Democrats with "safe" seats unlikely to face serious opposition for re-election. Fourteen of the eighteen Republican votes also hold safe seats. The amendment received 150 of its 163 votes from representatives with safe seats.

Among Democrats in the House from states with a majority vote for John Kerry in the 2004 Presidential election the amendment received support from 85% of the representatives, but only 48% of the Democrats from states that gave a majority vote to Bush voted for the amendment.

The amendment received 152 votes in 2003, the first time Hinchey attempted to attach it to appropriations bill for the Department of Justice. Four years later support for the measure is at 163 votes. Twelve of the Yes votes in 2003 have been lost in comparison with the 2006 vote, eight because of a change of mind by the representative and four due to a change in representatives. These lost 12 votes partially offset the 23 found yes votes in which votes against the measure in 2003 became votes for the amendment in 2006. Five of these changed votes are from districts that changed their representatives between the 2003 and 2006 votes.

Thirteen of the twenty-three votes gained over the four year period were from states with reform legislation.