JEFFERSON CITY, Mo. -- Americans used to getting warnings about the potential dangers of traveling overseas, but this summer, the NAACP put out an extraordinary warning about travel here at home -- in Missouri.

The warning advises "extreme caution," saying travelers could be subject to "discrimination and harassment."

"They're legalizing discrimination in the state of Missouri," says attorney Nimrod Chapel Jr., president of the NAACP in Missouri.

He says a bill recently signed into law by Republican Gov. Eric Greitens is so dangerous that he has a name for it.

"The Jim Crow bill," he says, "because in the eyes of the NAACP that's what it was breathing life into."

Nimrod Chapel Jr. CBS News

Currently, you can file a discrimination claim in the state of Missouri if things like race, religion and gender are a "contributing" factor to discrimination.

But later this month, alleged victims of discrimination would have to prove it is the "motivating" factor -- and Chapel says that's extremely hard to do.

"You would think that the best evidence would be, like, a memo. 'We discriminated against so-and-so because of who they are.' Nobody writes memos, or when they do it so rare, and then getting that kind of evidence can be very, very difficult," he says.

Pat Rowe Kerr CBS News

"It is wrong, it is flat out wrong," Pat Rowe Kerr says.

Kerr, 64, sued the state of Missouri in 2010 for sex and age discrimination. Last year, a jury awarded her nearly $3 million. Now, she's concerned the new law will make lawsuits like hers tougher to file and will send the wrong message.

"This is just another example of not being progressive, and if we want to be a progressive Missouri, why are we going backwards?" she asks.

Greitens calls the legislation common sense reform, and says the "motivating standard" is currently used by the U.S. Equal Employment Opportunity Commission. Meanwhile, the NAACP says it will continue to raise awareness through its travel advisory.