In his second inaugural address, President Obama offered a hint of the policies he will pursue and fight for in the next four years, arguing for action on climate change and defending entitlement programs that have been targeted for cuts.

Our current challenges, he argued, call for "collective action."

In contrast to his 2009 speech, Obama did not speak of moving past political divides. Instead, he made the case for his political principles.

"We have never relinquished our skepticism of central authority, nor have we succumbed to the fiction that all society’s ills can be cured through government alone," he said. "But we have always understood that when times change, so must we; that fidelity to our founding principles requires new responses to new challenges; that preserving our individual freedoms ultimately requires collective action."

Experience, he said, has shown that government intervention is needed for transportation, education, and regulation of the free market, as well as to care for the needy and protect people from catastrophe.

Obama defended entitlement programs that Republicans hope to reform as part of deficit-reduction cuts.

"The commitments we make to each other – through Medicare, and Medicaid, and Social Security – these things do not sap our initiative; they strengthen us," he said. "They do not make us a nation of takers; they free us to take the risks that make this country great."

He promised action on the climate, saying, "We will respond to the threat of climate change, knowing that the failure to do so would betray our children and future generations."

Obama also pledged his commitment to equal pay for women, as well as equal rights for gay Americans and voting reforms to avoid long lines at the polls. And he said touched on immigration reform, declaring that "our journey is not complete ... until bright young students and engineers are enlisted in our workforce rather than expelled from our country."

While he mentioned Newtown, Conn., saying that we must keep children across the country safe, the president did not speak of guns or gun control.

Little time was devoted to foreign policy, but he did commit to "try and resolve our differences with other nations peacefully" -- a suggestion that Obama will attempt new diplomatic outreach to Iran.