Do I need a passport to visit Arizona?

Such a question would have been laughable just months ago. As a U.S. citizen, of course there has never been a reason for me to carry my passport or other proof of residency / citizenship around with me regardless of where I am in the U.S. That is, until days ago when Arizona the legislature passed and the governor signed a law designed to combat the severe illegal immigration issues they face.
The new Arizona law will require police officers to arrest and detain anyone they have reasonable cause to believe may be in the U.S. illegally. If they pull you over for speeding or spot you hanging around a Home Depot parking lot waiting for a day labor job, they are required to arrest you if they think you’re an illegal immigrant. Period. Don’t have your passport or birth certificate with you? Do not pass Go. Do not collect $200. Go straight to jail.

For days, the media coverage on this issue has been polarized. The majority of the media has been overtly or implicitly negative. The exception is Fox News and other right wing media. I just don’t get it. As someone who has a history of voting for very conservative politicians, very liberal politicians, and very moderate politicians, this seems to me to be an issue that everyone across the entire spectrum of political leanings should be united against. Make no mistake about it: the law effectively requires everyone to carry with them at all times proof of citizenship / legal residency for even if you are a citizen, if you can’t prove it then the police MUST arrest and detain you if they have so much as probable cause to believe that you’re in the country illegally.
Many people believe that probable cause is equivalent to the burden imposed upon the state in a criminal. Nope. That’s reasonable doubt. What’s the difference? Kind of like night and day. Probable cause merely means more likely than not. In other words, if the police believe that there is a 51 percent change that you’re in the country illegally, they MUST arrest and detain you. If the standard were reasonable doubt, that’s in the high nineties and many judges define it as a 99 percent likelihood.
Some people that I’ve talked with say this isn’t a big deal because you would just show the police your driver’s license. But a driver’s license isn’t proof of citizenship or residency. Nor is your social security card or many, many other forms of identification issued by local, state, and even the federal government.
Some aren’t worried because they don’t look like an illegal immigrant, as if all illegal immigrants and no legal immigrants have a certain look or, dare we say, profile? These people seem to be saying without saying that if you’re Mexican then the police should arrest you, but they forget that Arizona was part of what is now Mexico so a huge portion of the population looks Mexican because they are, speak Spanish because that’s what their families have always spoken, and dress like Mexicans because that’s consistent with their culture. Should the police arrest and detain everyone who looks Mexican and speaks Spanish, even though probably hundreds of thousands of U.S. citizens fit that description in Arizona alone?
Other than countries like Nazi Germany, fascist Italy, North Korea, and Cuba, what countries detain their citizens for not carrying proof of residency / citizenship? This is an incredible broadening of the police powers of the state and should be VERY alarming to anyone who considers himself to be a conservative, liberal, or a libertarian. It seems to me that this is an issue that should easily unite the right, left, or middle yet I’m not hearing any concerns from the right. I just don’t get it.