When he was elected president in 2008, Barack Obama was untried and untested. Just four years out of the Illinois state Senate, he had not yet proved himself as either a manager or a leader. He had emerged from relative obscurity as the result of a single convention speech and was voted into office only a few years later on a tidal wave of hope, breezing past several opponents with far more experience and far clearer claims on the job.

Today, Obama is a very different candidate. He has confronted two inherited wars and the deepest recession since the Great Depression. He brought America's misguided adventure in Iraq to an end and arrested the economic downturn (though he did not fully reverse it) with the 2009 fiscal stimulus and a high-risk strategy to save the U.S. automobile industry. He secured passage of a historic healthcare reform law — the most important social legislation since Medicare.

Just as important, Obama brought a certain levelheadedness to the White House that had been in short supply during the previous eight years. While his opponents assailed him as a socialist and a Muslim and repeatedly challenged the location of his birthplace in an effort to call into question his legitimacy as president, he showed himself to be an adult, less an ideologue than a pragmatist, more cautious than cocky. Despite Republicans' persistent obstructionism, he pushed for — and enacted — stronger safeguards against another Wall Street meltdown and abusive financial industry practices. He cut the cost of student loans, persuaded auto manufacturers to take an almost unimaginable leap in fuel efficiency by 2025 and offered a temporary reprieve from deportation to young immigrants brought into the country illegally by their parents. He ended the morally bankrupt "don't ask, don't tell" policy that had institutionalized discrimination against gays in the military.

ENDORSEMENTS: The Times' recommendations for Nov. 6

The nation has been well served by President Obama's steady leadership. He deserves a second term.

His record is by no means perfect. His expansive use of executive power is troubling, as is his continuation of some of the indefensible national security policies of the George W. Bushadministration. This page has faulted him for not pushing harder for a comprehensive overhaul of immigration laws. Obama swept into office as a transformative figure, but the expectations built up by the long campaign thudded back to earth amid an unexpectedly steep recession and hyperbolic opposition from the right. That the GOP has sought to block his agenda wherever possible is undeniable, but truly great leaders find ways to bring opposing factions together when the times demand it; Obama has not yet been able to do so.

Republicans have sought to make the presidential election an up-or-down vote on Obama, hoping that voters will hold him accountable for the country's stubbornly high unemployment and sluggish economy. But this election isn't a referendum on one candidate, it's a choice between two. And unfortunately for the GOP, its candidate, former Massachusetts Gov. Mitt Romney, has demonstrated clearly that he's the wrong choice. He's wrong on the issues, from immigration to tax policy to the use of American power to gay rights and beyond. And his shifting positions and willingness to pander have raised questions about who he is and what he stands for.

On economic issues, the race between Obama and Romney presents a stark choice. Romney wants to cut taxes, spending and regulations in the hope that the mix of stimulus and austerity will spark growth and reduce the federal deficit. Obama wants to trim spending but raise taxes on high-income Americans, shrinking the deficit without sacrificing investments in the country's productive capacity or curtailing Washington's role in protecting the vulnerable.

The centerpiece of Romney's campaign is his plan to cut tax rates 20% below the Bush-era cuts while eliminating enough tax breaks to make up for the loss in revenue, after factoring in economic growth. But the plan lacks credibility, in no small part because Romney has declined to specify how he'd make the numbers work. The risk is that his tax reform will drive up costs for the very middle-income Americans he says he wants to protect, who are the biggest beneficiaries of those tax breaks.

In fact, it's irresponsible to seek a deep, permanent tax cut when the government is deeply in the red. And Romney would exacerbate the situation by spending extravagantly on defense even as the last of the Bush-era wars ends. His main proposal for reducing the deficit is to cap federal spending at 20% of the economy. With Social Security and Medicare commitments growing in tandem with the rising population of retirees, however, such a cap would inevitably force draconian cuts in federal programs that are vital to productivity, such as higher education, transportation and research.

It's hard to analyze the effect of Romney's plans because he's left so many blanks to be filled in after the election. For example, he wants to replace the healthcare and financial regulatory reforms enacted in 2010, but he won't say with what exactly. He's also advocated rolling back the clock on clean energy, overturning Roe v. Wade and leaving women's reproductive rights at the mercy of state legislators and abandoning efforts to help distressed borrowers keep their homes. And he has sounded bellicose on foreign policy, particularly in regard to the complex challenges posed by Iran, Russia and China, with which he appears determined to start a trade war.

The most troubling aspect of Romney's candidacy is that we still don't know what his principles are. Is he the relatively moderate Republican who was governor of Massachusetts, the "severely conservative" one on display in the GOP primaries or the more reasonable-sounding fellow who reappeared at the presidential debates? His modulating positions on his own tax plan, healthcare reform, financial regulation, Medicare, immigration and the national safety net add to the impression that the only thing he really stands for is his own election.

Voters face a momentous choice in November between two candidates offering sharply different prescriptions for what ails the country. Obama's recalls the successful formula of the 1990s, when the government raised taxes and slowed spending to close the deficit. The alternative offered by Romney would neglect the country's infrastructure and human resources for the sake of yet another tax cut and a larger defense budget than even the Pentagon is seeking. The Times urges voters to reelect Obama.