Hillary Rodham Clinton speaks to reporters at the United Nations on March 10. (AP/Seth Wenig)

Hillary Rodham Clinton didn't say much in the video announcing her campaign for president.

She said she was running for president. That was big. "The deck is still stacked in favor of those at the top," she said, adding, "When families are strong, America is strong." Both of those things could be true, but they don't answer the question of what Clinton would actually do as president.

The announcement by the former secretary of state contrasted with those by her rivals in the Republican primary so far, which gave voters an overall idea of how the candidates would govern. Monday night, Sen. Marco Rubio (R-Fla.) promised to "repeal and replace Obamacare" and to rescind "this administration’s dangerous concessions to Iran." Sen. Rand Paul (R-Ky.) said last week he thinks Congress should balance the budget every year. And Sen. Ted Cruz (R-Tex.) proposed abolishing the Internal Revenue Service and establishing a flat tax.

You might disagree with these ideas and the others the Republican candidates have floated so far, but they have put them on the table for discussion. Clinton's announcement was more generic. Jon Stewart compared it to a "State Farm commercial gone viral."

As the campaign progresses, though, the author of a memoir titled "Hard Choices" will have to make several about which policies she'll support.  Here are three key questions that could be challenging for her campaign.

Will Clinton support the trade deal in the Pacific?

The Obama administration has been negotiating a free-trade treaty with dozens of other Pacific countries. The final terms of the deal, known as the Trans-Pacific Partnership, haven't been worked out yet, but when they are, the Senate will be asked to take an up-or-down vote to ratify the agreement. And Clinton will probably be asked how she would vote.

When her husband was in office, he oversaw the North American Free Trade Agreement, which critics argue reduced wages for the U.S. working class. Unions still haven't forgiven President Clinton, and some reports have suggested that labor won't make donations to candidates who support Obama's deal in next year's campaign.

"Bill Clinton still gets screamed at about NAFTA by working people," AFL-CIO President Richard L. Trumka told The Washington Post last month. "There's no reason to believe that TPP will be a break from the NAFTA model. I haven't seen it yet."

Hillary Clinton called NAFTA "a mistake" in 2007, but she supported the TPP and supervised negotiations as Obama's first secretary of state. The politics of the issue are treacherous. Many Democratic donors believe a trade deal will improve the economy, but labor is itself an major source of cash for the party.

It's not just members of unions who might be opposed. In fact, a 2010 survey by the Pew Research Center suggests that it's independent and Republican voters who are most skeptical of free trade. The survey found that 63 percent of Republicans identifying with the tea party -- the most for any group -- said that free trade had been bad for the country. About half of independents also said that free trade had led to layoffs and lower wages. (Economists disagree about the effects of free trade agreements, or even about whether they have much effect at all.)

Stopping the government from interfering with the market is usually a conservative goal, so it's somewhat surprising that these voters are opposed to free trade. Maybe they associate it with Clinton's husband.

Maybe they have more conservative views about American geopolitical power. By their nature, free trade agreements bind the country to international rules, and the Pacific treaty under negotiation would allow foreign companies to force the U.S. government into court before international tribunals.

If Clinton is the nominee, some observers say she'll need to do well among politically moderate, working-class white voters in order to win the election. Whatever the reason, support for the Pacific deal could be interpreted among this group as a capitulation to big money.

What does Clinton think about standardized testing in schools?

Like free trade, public education is an issue that sets two important Democratic constituencies against each other: schoolteachers and advocates for civil rights.

The Obama administration's policies -- which encouraged states to evaluate teachers based on their students' test scores, for example -- have alienated many parents and educators.  The country's largest teachers union called for the resignation of Obama's education secretary, Arne Duncan, last year. Duncan has remained in his position, but the administration has tempered some of its rhetoric, especially around testing.

The administration also encouraged the widespread adoption of a set of educational standards known as the Common Core, which many teachers complain are interfering with their work. The standards describe what children should be able to do at the end of kindergarten through 12th grade in reading and math. Many people associated them with the Obama administration, although they were initially developed by a activists and state education officials. Students across the country are being tested against these standards for the first time this spring.

Clinton might be wary of some of the popular anger against testing. And as Maggie Haberman reports in The New York Times, Clinton is a personal friend of Randi Weingarten, who leads the country's other major teachers union, the American Federation of Teachers.

Yet if she takes a stance against standardized testing, Clinton risks alienating civil rights advocates, who see tests as a way to ensure that the public schools treat black and Hispanic students fairly. Given all of the speculation about whether Clinton will be able to replicate Obama's successes among racial and ethnic minorities, it has to be a question she and her advisers are thinking about carefully.

Clinton might be able to avoid this question, but Congress is working to overhaul No Child Left Behind, the law signed by President Bush that inaugurated the current era of annual testing for every student. If the bill makes it to Obama's desk, Clinton might be asked for her position on it.

The good news is that a bill in the Senate has the support of Republicans, Democrats, teachers unions and civil rights leaders. A real compromise could draw some of the political toxin out of the issue.

Will Clinton propose an expansion of Social Security?

Many liberals have urged Sen. Elizabeth Warren (D-Mass.), a populist firebrand and a vocal opponent of the trade deal, to challenge Clinton for the Democratic nomination. Warren has said she won't run, but she is going to continue pushing for more generous Social Security benefits. All but two Democratic senators voted for her proposal earlier this month.

Warren's argument is simple. More and more Americans are saving in individually held, 401(k) plans rather than in traditional defined-benefit pensions, exposing them to losses in the stock market. As a result, many older citizens watched their savings evaporate in the financial crisis, and Social Security's benefits aren't enough to live on. The language of her proposal suggests an increase in taxes to allow the program to make more generous payments.

Conservatives reject this line of reasoning, as do think tanks like the Center for American Progress and Third Way. Critics of Warren argue that it would be cheaper to pay more generous benefits only to elderly citizens with the least to live on, and less to those who don't need Social Security to get by.

All the same, as Jamelle Bouie explains at Slate, Warren has changed the way Democratic lawmakers think about Social Security. Just a few years ago, Democrats were ready to join Obama in offering to reduce benefits as part of a "grand bargain" with the Republican opposition in exchange for a tax increase.

Has Clinton been persuaded as well? We don't know yet. Laura Meckler reports in The Wall Street Journal that in Clinton's last public comments on the issue, she supported a bipartisan commission that would presumably recommend a combination of reduced benefits and increased taxes to make sure Social Security has enough money to keep sending out checks over the long term.

"I am totally committed to making sure Social Security is solvent," Clinton said in 2008. The program is currently projected to be able to meet its obligations for just a couple of decades -- as long Congress shifts some funds from the program for retirees to the much smaller program for the disabled. If Congress acts, both would last until 2033.

Yet if Congress doesn't act by late next year, disabled beneficiaries of Social Security will start getting checks that are 20 percent smaller. Republicans have indicated they don't want to fund disability past that point without some kind of agreement on how to maintain the program's solvency overall.

All that is to say that Clinton will be asked about Social Security once again during this campaign.