Opinions are sharply divided on the politically-charged measure, S.B. 1062, approved last week by the state's Republican-led legislature and now at Brewer's desk.
It proposes to give Arizona businesses that assert their religious beliefs the right to deny service to gay and lesbian customers.
Brewer returned home on Tuesday from a weekend in Washington with her state roiling over a values clash between arch conservatives and same-sex advocates that is playing out in different ways in courts, state legislatures and on Main Street across the country.
The Arizona measure is particularly pointed and is supported by vocal proponents. They stridently contend it is their legal right to oppose what they see as a gay-rights agenda nationally, which includes same-sex lifestyles and related government mandates.
In this case, however, their beliefs clash with everyday businesses, who don't agree that the assertive law would be good for the Arizona economy or reflect positively on their enterprises.
They also fear discrimination lawsuits, boycotts and other disruptions that could further harm their interests.
Although it's expected that she'll veto the bill, Brewer did not indicate her intentions either way during an interview with CNN on Monday in Washington, where she attended a meeting of governors.
"I can assure you, as always, I will do the right thing for the state of Arizona," she said.
Republican lawmakers who know her well said they believe those comments suggest that she'll reject it.
Brewer has until Saturday to act.
The bill also has drawn fire from those considered to be "establishment" Republicans, who in this case include lawmakers with generally social conservative beliefs.
Arizona Sens John McCain and Jeff Flake have publicly urged Brewer to veto the measure, citing worries about the economic impact on the state's businesses.
Former Massachusetts governor and Republican presidential nominee Mitt Romney recently tweeted that he feels a veto of the bill is the right course.
Large businesses including Apple, American Airlines, AT&T, and Intel, have also voiced opposition and the Arizona Super Bowl Host Committee has expressed concerns.
Republican Arizona state Rep. Heather Carter, one of three state house Republicans who voted against this bill said she "knew this would be an important vote."
Carter said in the moments just after the bill passed the state Senate and before the House vote, she had a "ground swell" of phone calls and emails from friends, family, and other people she respects telling her "you can't vote for this bill, it's a bad bill."
This reaction, she said, told her something. She could not vote for the bill if there was "even the off-chance that discrimination could happen."
The measure, which was pushed by the Center for Arizona Policy, a conservative group opposed to abortion and same-sex marriage, has also drawn staunch support from those who say the federal courts have increasingly pushed a pro-gay rights agenda.
Conservative radio host Rush Limbaugh said on his show that Brewer is "being bullied by the homosexual lobby in Arizona and elsewhere" on the measure.
Supporters also see, in the opposition, a double standard in how the rights of gays and lesbians are supported versus those who have conservative religious views.
"You have a gay person that owns a printing shop, OK. Somebody from the Westboro Baptist Church comes in there and demands that they print and sign that, obviously the printer is not going to agree with. Should that religious group demand that print shop print that thing," Republican Arizona state Rep. Sonny Borrelli said on CNN.
Protestors on both sides are also active.
After the bill passed, Rocco's Little Chicago Pizzeria in Tucson placed a sign in its window stating "We reserve the right to refuse service to Arizona legislators."
The restaurant's Facebook page received more than 20,000 likes for the sign and comments from fans saying things like "Y'all rock! Stand up for human rights!"
Gay-rights activists stood outside the state Capitol building in Phoenix on Friday to protest the measure and additional protests are planned though out the week.
The Arizona Catholic Conference released a statement urging supporters to encourage Brewer to sign the bill into law.
"The threats to religious liberty have become very real... S.B. 1062 will help avoid the situations being experienced around the country where businesses are being forced to close because of their owners' faith," the organization's statement read.