Even easier with a link: SB1070 PDF. Also, here's the Arizona Senate fact sheet.

The first point in the latter document sounds like the bill is actually even stricter than just allowing document checks:

Requires a reasonable attempt to be made to determine the immigration status of a person during any legitimate contact made by an official or agency of the state or a county, city, town or political subdivision (political subdivision) if reasonable suspicion exists that the person is an alien who is unlawfully present in the U.S.

The word "requires" is pretty clear, but I actually didn't see it in the official text of the bill, so bottom line, not so clear.

Another part of the bill has yet to get any attention, but I suspect it will once people work through all the other stuff. To me, it's a sure sign that a legislature is reaching too far when it tries to create "legal derivatives": By analogy with credit derivatives, this is a law that doesn't criminalize anything new, but criminalizes violatiing another law. Kind of a doubling-down on the offender. SB1070 1) creates a special definition of "trespassing" that applies only to illegal immigrants, and boils down to "breathing while in Arizona"; 2) Stipulates additional penalties on top of the penalties for trespassing that a citizen would suffer. I'll return that latter point in a moment (can you say 14th Amendment?), but for completeness, here's the trespassing section:

13-1509. Trespassing by illegal aliens; assessment; exception;
41 classification
42 A. IN ADDITION TO ANY VIOLATION OF FEDERAL LAW, A PERSON IS GUILTY OF
43 TRESPASSING IF THE PERSON IS BOTH:
44 1. PRESENT ON ANY PUBLIC OR PRIVATE LAND IN THIS STATE.
45 2. IN VIOLATION OF 8 UNITED STATES CODE SECTION 1304(e) OR 1306(a).
S.B. 1070
- 3 -
1 B. IN THE ENFORCEMENT OF THIS SECTION, THE FINAL DETERMINATION OF AN
2 ALIEN'S IMMIGRATION STATUS SHALL BE DETERMINED BY EITHER:
3 1. A LAW ENFORCEMENT OFFICER WHO IS AUTHORIZED BY THE FEDERAL
4 GOVERNMENT TO VERIFY OR ASCERTAIN AN ALIEN'S IMMIGRATION STATUS.
5 2. A LAW ENFORCEMENT OFFICER OR AGENCY COMMUNICATING WITH THE UNITED
6 STATES IMMIGRATION AND CUSTOMS ENFORCEMENT OR THE UNITED STATES BORDER
7 PROTECTION PURSUANT TO 8 UNITED STATES CODE SECTION 1373(c).
8 C. A PERSON WHO IS SENTENCED PURSUANT TO THIS SECTION IS NOT ELIGIBLE
9 FOR SUSPENSION OR COMMUTATION OF SENTENCE OR RELEASE ON ANY BASIS UNTIL THE
10 SENTENCE IMPOSED IS SERVED.
11 D. IN ADDITION TO ANY OTHER PENALTY PRESCRIBED BY LAW, THE COURT SHALL
12 ORDER THE PERSON TO PAY JAIL COSTS AND AN ADDITIONAL ASSESSMENT IN THE
13 FOLLOWING AMOUNTS:
14 1. AT LEAST FIVE HUNDRED DOLLARS FOR A FIRST VIOLATION.
15 2. TWICE THE AMOUNT SPECIFIED IN PARAGRAPH 1 OF THIS SUBSECTION IF THE
16 PERSON WAS PREVIOUSLY SUBJECT TO AN ASSESSMENT PURSUANT TO THIS SUBSECTION.
17 E. A COURT SHALL COLLECT THE ASSESSMENTS PRESCRIBED IN SUBSECTION D OF
18 THIS SECTION AND REMIT THE ASSESSMENTS TO THE DEPARTMENT OF PUBLIC SAFETY,
19 WHICH SHALL ESTABLISH A SPECIAL SUBACCOUNT FOR THE MONIES IN THE ACCOUNT
20 ESTABLISHED FOR THE GANG AND IMMIGRATION INTELLIGENCE TEAM ENFORCEMENT
21 MISSION APPROPRIATION. MONIES IN THE SPECIAL SUBACCOUNT ARE SUBJECT TO
22 LEGISLATIVE APPROPRIATION FOR DISTRIBUTION FOR GANG AND IMMIGRATION
23 ENFORCEMENT AND FOR COUNTY JAIL REIMBURSEMENT COSTS RELATING TO ILLEGAL
24 IMMIGRATION.
25 F. THIS SECTION DOES NOT APPLY TO A PERSON WHO MAINTAINS AUTHORIZATION
26 FROM THE FEDERAL GOVERNMENT TO REMAIN IN THE UNITED STATES.
27 G. A VIOLATION OF THIS SECTION IS A CLASS 1 MISDEMEANOR, EXCEPT THAT A
28 VIOLATION OF THIS SECTION IS:
29 1. A CLASS 3 FELONY IF THE PERSON VIOLATES THIS SECTION WHILE IN
30 POSSESSION OF ANY OF THE FOLLOWING:
31 (a) A DANGEROUS DRUG AS DEFINED IN SECTION 13-3401.
32 (b) PRECURSOR CHEMICALS THAT ARE USED IN THE MANUFACTURING OF
33 METHAMPHETAMINE IN VIOLATION OF SECTION 13-3404.01.
34 (c) A DEADLY WEAPON OR A DANGEROUS INSTRUMENT, AS DEFINED IN SECTION
35 13-105.
36 (d) PROPERTY THAT IS USED FOR THE PURPOSE OF COMMITTING AN ACT OF
37 TERRORISM AS PRESCRIBED IN SECTION 13-2308.01.
38 2. A CLASS 4 FELONY IF THE PERSON EITHER:
39 (a) IS CONVICTED OF A SECOND OR SUBSEQUENT VIOLATION OF THIS SECTION.
40 (b) WITHIN SIXTY MONTHS BEFORE THE VIOLATION, HAS BEEN REMOVED FROM
41 THE UNITED STATES PURSUANT TO 8 UNITED STATES CODE SECTION 1229a OR HAS
42 ACCEPTED A VOLUNTARY REMOVAL FROM THE UNITED STATES PURSUANT TO 8 UNITED
43 STATES CODE SECTION 1229c.

(Emphasis mine)

It looks to me like this bill doesn't just reinforce existing Federal law, it weights the penalties for other, non-immigration laws, disproportionately against illegal immigrants. The problem? Here's the 14th Amendment:

Section 1. All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.

The first half says that states have to treat citizens equally, but be careful with the rest of it: The part about equal protection of the law doesn't apply just to citizens, but to all "persons" without regard to the status of their papers.

It's not equal protection when a person's violation of one law then leads to unequal treatment under another and unrelated law. I can't imagine any court being fooled by the dodge of trying to define a different kind of trespass for illegals. It's sufficient that they're illegals, and it's unfair and discriminatory to pile on unrelated penalties.

My thoughts on the 14th Amendment are my own, but when I consulted a Wikipedia article on the Equal Protection Clause, I found my views are pretty much in accord with mainstream legal interpretion. Partly it's because it's pretty clear and commonsensical, but also because the Equal Protection Clause expresses a principle that should be universal. As Wikipedia puts it:

The Equal Protection Clause can be seen as an attempt to secure the promise of the United States' professed commitment to the proposition that "all men are created equal"[2] by empowering the judiciary to enforce that principle against the states.

I haven't seen much talk about principle and morality in this whole mess, and that's too bad. The lawyers can debate the niceties until hell freezes over, but my moral compass is simply deeply offended by the Arizona law. Everything else is about building a rational case to back it up.