The California chapter of the League of United Latin American Citizens (LULAC) is questioning the legitimacy of the 1848 Treaty of Guadalupe Hidalgo and the resultant location of the border between the United States and Mexico (further defined by the subsequent 1854 Gadsden Purchase).
LULAC California is focusing on the 2008 Supreme Court decision in the case of Medellin v. Texas, regarding a Mexican national who had been sentenced to death by a Texas court. In this case, the Supreme Court ruled that while an international treaty may constitute an international commitment, it is not binding domestic law unless Congress has enacted statutes implementing it or unless the treaty itself is "self-executing"; that decisions of the International Court of Justice are not binding domestic law; and that, absent an act of Congress or Constitutional authority, the President of the United States lacks the power to enforce international treaties or decisions of the International Court of Justice.
As a result, LULAC California believes this case calls for a renegotiation of the treaty, since they claim that Congress failed to make it binding upon individual states. Here's a YouTube video of a Lou Dobbs report on the story:
The LULAC national headquarters had no comment on the claims of their California chapter. But ALIPAC is outraged, which is no surprise considering that when VDARE compared native-born vs. foreign-born employment in the United States, they found that while foreign-born employment increased 33.7 percent between 2000 and 2008, native-born employment only increased 3.8 percent during the same period.
LULAC's gambit is a Hail Mary pass that's unlikely to go anywhere. But it shows how desperate the immigrant lobbies are to get illegals legitimized.