The Humane Society of the United States urged state legislators on August 13 to join the fight against the House version of the farm bill, which includes the King amendment. The King amendment, critics say, has the potential to nullify more than 150 state laws affecting agriculture, including California's Proposition 2, which aims at ending the use of battery cages for laying hens.

The King amendment was included in the House version of the farm bill that passed on July 11. However, it was not part of the Senate farm bill that was approved on June 10. The farm bill's fate is now with a team of negotiators from both the House and Senate.

The Humane Society of the United States, which hosted a press conference with state legislators from the National Conference of State Legislators on August 13, has been successful in getting some state lawmakers to join its fight. The National Conference of State Legislators has sent a letter to both House and Senate committee leaders, urging them to remove the King amendment from the farm bill.

National Conference of State Legislators leaders Rep. Terie Norelli, D-NH, and Sen. Bruce Starr, R-Ore, wrote to Congressional leaders that the King amendment "would preempt vital state agricultural policies designed to protect the safety and well-being of our farmland, waterways, forests and most importantly, our constituents." The two state lawmakers also asserted in the letter that the King amendment would have harmful economic impacts to certain states, according to a news release from the Humane Society of the United States.