* President lays out broad agenda for second term
* Seeing government as a protector of the vulnerable
* Republicans see a "liberal checklist"
By Steve Holland
WASHINGTON, Jan 21 (Reuters) - Republican President Ronald Reagan declared in 1981 that "government is not the solution to our problem; government is the problem." Fifteen years later, Democratic President Clinton declared that "the era of big government is over."
That wasn't exactly President Barack Obama's message in his second inaugural address on Monday.
In a spirited defense of government's role as a protector of society's most vulnerable people, the Democratic president signaled a determination to protect costly social programs that have been targeted by Republicans seeking to reduce growth in the $16.4 trillion U.S. debt.
In a series of implied jabs at uncompromising conservatives who have fostered gridlock in Congress and cast him as an un-American socialist, Obama essentially portrayed such critics as being outside the mainstream of U.S. politics.
"We cannot mistake absolutism for principle, or substitute spectacle for politics, or treat name-calling as reasoned debate," Obama said during his 18-minute speech.
Laying out a broad vision for his second four-year term, Obama delivered a speech that struck many of the themes that ran through his re-election campaign.
Chief among them: a call to increase opportunities for the middle class and "reject the idea that America must choose between caring for the generation that built this country and investing in the generation that will build its future."
Such comments struck a nerve with some Republicans, who saw them as a sign that Obama might be unwilling to make significant cuts to the Medicare and Medicaid healthcare programs and the Social Security retirement program - and that the president might seek more tax increases on the nation's richest people.
Cutting back on those "entitlement" programs is widely viewed as a significant part of reducing the budget deficit.
"It was a speech outlining vigorous support for expanding the size and reach of government - at a time when there is a national call for, and bipartisan support of, reduced Washington spending," said Don Stewart, spokesman for Republican Mitch McConnell of Kentucky, the Senate minority leader.
READY FOR A FIGHT
Obama begins his second term having stared down Republicans on tax and spending issues at the end of December, achieving a deal that raised taxes on the country's highest earners.
The stage is now set for the next round of fiscal wrangling: Obama wants to revamp the tax code to eliminate a myriad tax loopholes while fending off Republicans' demands for deep spending cuts.
His graying hair and lined face providing proof, Obama appears battle-hardened after his first term, now accustomed to the idea that Republicans will fight him at nearly every turn and determined to muscle as much of his agenda as possible through the divided Congress.
In defending social programs, Obama offered a subtle reminder of comments last May by Republican presidential candidate Mitt Romney, who told supporters at a private fund-raiser that 47 percent of Americans were dependent on government programs and benefits, and therefore were unlikely to support Romney.
"The commitments we make to each other, through Medicare and Medicaid and Social Security, these things do not sap our initiative. They strengthen us," Obama said. "They do not make us a nation of takers. They free us to take the risks that make this country great."
Such talk appeared to foreshadow more ideological fights in Congress over taxes and spending, which have consumed Washington during the past four years.
A 'LIBERAL CHECKLIST'
Obama seemed to claim a far-reaching mandate in his inaugural address, vowing action on issues such as climate change, immigration and gay rights.
Those issues were largely on the sidelines during most of Obama's first term, although he did express support for legalized same-sex marriage.
An agreement to revamp the immigration system seems the most likely bipartisan achievement. Obama wants such a deal and so do Republicans in Congress, after having seen Hispanics vote overwhelmingly for the Democrats in the Nov. 6 election.
Far less certain is how Obama might follow through on his pledge to address climate change in a significant way.
"He laid out a very activist agenda," said presidential scholar Thomas Alan Schwartz of Vanderbilt University. "My interpretation would be that he really does feel that the wind is at his back, that he has a very favorable environment to push right now on a wide range of issues."
Republicans listening for clues as to what to expect from Obama in the coming months did not hear much conciliatory talk.
"It was a liberal checklist," said one aide to a senior Republican in Congress. "I didn't hear any outreach to conservatives or the half of the country who didn't think he should be president. He was speaking to the people who voted for him. That's fine, but it wasn't a call for unity. It wasn't a call for smaller government. It was a call for bigger government."
Republican Senator Rob Portman of Ohio said Obama "missed the opportunity to talk about where we can find common ground."
'WE CANNOT AFFORD DELAY'
Monday's events essentially start the clock ticking for Obama. Realistically he has one to two years to achieve most of his agenda before Washington's attention turns to the 2016 election when America will vote for a new president.
"We cannot afford delay," Obama said.
Still faced with a bitterly partisan environment in which Republicans control the House of Representatives and Democrats lead the Senate, White House officials say Obama will work with Congress when he can and use executive orders to implement policy when possible.
At the same time, his presidential campaign apparatus is being rebooted to act as a populist support group to push for his policies.
So how much can he get done?
Second terms often are marked by overreaching by the president, a misreading of the public mood.
For example, Republican George W. Bush pushed for an overhaul of Social Security at the outset of his second term. It quickly ran afoul of public opinion and went nowhere.
Obama has acknowledged the risk of a too-ambitious agenda. But having outmaneuvered Republicans on taxes and spending thus far - and with significantly better favorability ratings than they have - Obama appears determined to pursue a large second-term agenda.
"Certainly he is well-positioned right now," said Peverill Squire, a political science professor at the University of Missouri. "Republicans are having trouble being as aggressive as they have been. I suspect he may be able to cut a few more deals." (Editing by David Lindsey and Christopher Wilson)