Kansas Secretary of State Kris Kobach says Wednesday's Supreme Court arguments over Arizona's immigration law will test the relationship between Washington and local governments.

The Court is hearing arguments over the constitutionality of SB 1070, the well-known Arizona statute Kobach helped draft. The law gives Arizona's police broad powers to investigate allegedly illegal immigration, and the White House wants it struck down as an improper intrusion on federal power.

"If the Obama administration's argument wins in court, then we will be in uncharted waters," Kobach said. "Because any executive memo or executive order or executive policy statement could have the effect of nullifying state laws across the land."

Kobach says he hasn't decided if he can go to Washington for Wednesday's arguments.

He also says he remains an informal adviser to Mitt Romney, the GOP's almost-certain nominee for president.

Kobach's status with the Romney campaign became an issue last week, when the controversial local Republican was left off a published list of advisers to the GOP candidate.