In the biggest speech of his still young political career, GOP vice presidential nominee Paul Ryan told the Republican National Convention on Wednesday that time is running out to solve the nation's fiscal problems, but Mitt Romney and he can do it if elected in November.

"We will not duck the tough issues -- we will lead," Ryan said in his prime time address televised nationwide. "... The work ahead will be hard. These times demand the best of us -- all of us, but we can do this. Together, we can do this."

Ryan's speech was part of a campaign effort to portray Romney, a multimillionaire businessman and former Massachusetts governor, as a champion of working-class Americans who struggle under the policies of President Barack Obama.

Romney chose Ryan, the conservative House Budget Committee chairman from Wisconsin, as his running mate in hopes that the fiscal expert known for big and hard-line ideas would galvanize support on the political right and appeal to moderates and independents seeking solutions for the nation's chronic deficit and debt problems.

Ryan's speech delivered a fiery attack on Obama's record and highlighted the GOP allegiance to founding principles as he decried a dearth of leadership and pledged results in keeping with the convention theme for the day: "We Can Change It."

"I accept the calling of my generation to give our children the America that was given to us, with opportunity for the young and security for the old -- and I know that we are ready," Ryan said. "Our nominee is sure ready. His whole life has prepared him for this moment -- to meet serious challenges in a serious way, without excuses and idle words. After four years of getting the runaround, America needs a turnaround, and the man for the job is Gov. Mitt Romney."

Ryan focused mostly on the fiscal issues that are the congressman's strength, such as the national debt, stimulus spending under Obama and his proposed Medicare reforms, which have come under attack by Obama and Democrats.

He sought to turn the tables on the issue, repeating the factually challenged assertion that Obama cut Medicare by more than $700 billion to cover the costs of the 2010 health care reform law passed by Democrats.

The figure comes from a Jully 24 Congressional Budget Office report that said repealing the health care law, as called for by Romney and Ryan, would increase spending on Medicare by $716 billion through 2022. At the same time, the CBO letter said keeping Obamacare in place would not mean a $716 billion decrease in Medicare spending, as claimed by Ryan.

"The president has declared that the debate over government-controlled health care is over," Ryan said. "That will come as news to the millions of Americans who will elect Mitt Romney so we can repeal Obamacare."

If elected, he and Romney will confront the tough issues "before the math and the momentum overwhelm us all," Ryan added.

His speech included some humorous jabs at Obama that drew laughs and ovations from a charged convention crowd.

"With all their attack ads, the president is just throwing away money -- and he's pretty experienced at that," Ryan said early in the speech. Later, he received a standing ovation when he asked: "Without a change in leadership, why would the next four years be any different from the last four years?"

Ryan also peppered his remarks with references to central government planning and control, code words for socialism among the most conservative elements of the Republican Party.

"None of us should have to settle for the best this administration offers -- a dull, adventureless journey from one entitlement to the next, a government-planned life, a country where everything is free but us," he said.

In the most emotional moment, Ryan paid tribute to his mother, who started her own business after his father died.

"It was a new life, and it transformed my mom from a widow in grief to a small businesswoman whose happiness wasn't just in the past," Ryan said. "Her work gave her hope. It made our family proud. And to this day, my mom is my role model."

In the VIP box of the Tampa Bay Times Forum, Ryan's mother, Betty, stood and waved, and he touched his heart with his hand while gazing at her.

In other speeches Wednesday night, Sens. Rand Paul of Kentucky and John McCain of Arizona offered biting criticism of Obama's presidency, saying the president was failing to adhere to American values.

Paul took aim at domestic policies that he blamed for the country's debt now equaling its economic production, calling Obama "uniquely unqualified to lead this great nation."

"The republic of Washington and Jefferson is now in danger of becoming the nation of debt and despair," said Paul, the son of vanquished Republican candidate Rep. Ron Paul of Texas.

McCain, the Republican presidential candidate defeated by Obama four years ago, took aim at what he called diminishing American power and influence around the world. He accused Obama of abandoning freedom movements in Iran and Syria by not supporting protesters trying to overthrow oppressive regimes, saying "our president is not being true to our values."

"We can choose to follow a declining path, toward a future that is dimmer and more dangerous than our past, or we can choose to reform our failing government, revitalize our ailing economy, and renew the foundations of our power and leadership in the world," said McCain, a consistent advocate for a stronger military. "That is what's at stake in this election."

Former Secretary of State Condoleezza Rice added her voice to the call for American strength through power, delivering a politically charged speech that accused Obama of yielding the nation's leadership role in the world.

"It just has to be that the freest and most compassionate country on the face of the Earth will continue to be the most powerful," Rice said to cheers.