Obama, McCain praise country's revolutionary heritage

"That is the spirit we are called to show once more," Obama said. "We are facing an array of challenges on a scale unseen in our time. We are waging two wars. We are battling a deep recession. And our economy – and our nation itself – are endangered by festering problems we have kicked down the road for far too long: spiraling health care costs, inadequate schools and a dependence on foreign oil."

America had to correct injustices – slavery, segregation, the disenfranchisement of women – to fulfill that promise, and the crisis over the disputed Iranian election offers America another chance to stand with liberty on the right side of history, he said.

"Today, we stand with the millions of Iranians who brave batons, imprisonment and gunfire to have their voices heard and their votes counted," McCain said. "They do not ask us to arm them or come to their assistance with anything other than public declarations of solidarity and public denunciations of the tyrants who oppress them. We have a moral obligation to do so."

While McCain pushed for a more forceful international voice, Obama rallied support for his domestic programs.

Obama said America's "unyielding spirit" is needed to overcome "naysayers" and to deal with problems "we cannot defer any longer," in particular revamping the education system, overhauling the health care system and making clean energy profitable to end dependence on foreign oil.

"That is how this generation of Americans will make its mark on history. That is how we will make the most of this extraordinary moment," he said. "And that is how we will write the next chapter in the great American story."

An energy bill backed by Obama narrowly passed the House, and Congress is embroiled in competing bills to overhaul the health care system. Questions about cost have dogged both issues.

McCain also stepped into ongoing political issues with his call for more vocal support to Iranian election protesters.

Obama expressed doubts about the legitimacy of the June 12 presidential election, which official results gave to President Mahmoud Ahmadinejad, and said the world "bore witness" to the quashed street protests. But Republican lawmakers have pushed the president to more forcefully denounce Iran's leadership.

“There are those among us who warn that a strong and unequivocal declaration of moral support for Iranians would be used by the cruel regime ... to convince their subject people that the United States is behind the civil unrest," McCain said.

"Do they really believe Iranians don't know why they're protesting and who is oppressing them? ... Iranians know the truth. They know who is oppressing them and why."

Iranian leaders have portrayed the unrest as sparked by foreign meddling, calling opposition leader Mir Hossein Mousavi a U.S. agent, saying the CIA shot street protesters and arresting British Embassy employees.

"These brave and determined Iranians ... are on the right side of history," McCain said. "Liberty and justice will someday be theirs. Let us hope they will have reason to remember then who their friends were in their struggle for freedom."

Whether on the domestic or international scene, the political leaders called for Americans to bring their revolutionary heritage to bear on present problems.

"We, as a people, did not get here by standing pat in a time of change," Obama said. "We did not get here by doing what was easy. That is not how a cluster of 13 colonies became the United States of America.

"We are not a people who fear the future. We are a people who make it. ... And on this July Fourth, we need to summon that spirit once more."