After years of struggle to fix the federal budget mess, U.S. Sen. Mark Warner is in a familiar place.

Decades ago, not long after graduating from Harvard Law School, he stumbled repeatedly in his quest to be an entrepreneur.

He lost $5,000 - his life savings - in six months trying to sell an additive intended to make oil furnaces run more efficiently. Flat broke, he tried the real estate business in Atlanta but failed at that, too.

In 1982, his luck changed when he became interested in cellular phones. An early player who persuaded others to invest in the new industry, Warner struck it rich. As a venture capitalist, he built a personal fortune that is worth, on average, about $228 million, according to an analysis of the Virginia Democrat's 2012 financial disclosure filing by the Center for Responsive Politics.

Taking his business acumen to Richmond in 2002 when he was elected governor, Warner stumbled again.

During his first two years, he struggled to deal with an inherited multibillion-dollar state revenue shortfall while failing to gain traction on other initiatives. The Republican-dominated General Assembly didn't take him or his proposals seriously.

By his third year, he regrouped, developing and successfully championing a broad recovery plan - including a $1 billion tax increase - that he persuaded a bipartisan majority of the legislature to approve. His plan is credited with sparking Virginia's economic revival.

"If you can find common ground," Warner said in 2006, "you can get things done."

Today, at age 58, Warner is in the fifth year of his six-year Senate term, trying again to persuade others to follow his lead - or at least join a bipartisan crusade - to solve a national problem: getting control of a fast-growing national debt that he and others say is stifling a slow-moving economy.

"There's been no issue on which I've spent more time trying to reach out," Warner said Wednesday during a Senate floor speech on stalled budget negotiations. "I understand some of my colleagues actually avoid me in the hallways now because they fear they're going to get the 'Mark Warner harangue' on the debt and deficit."

With only months remaining until a divided Congress shifts to re-election mode, the prospects of bipartisan compromise are dimming. All 435 House seats and 33 Senate seats, including Warner's, will be up for grabs.

"I think this is our last, best chance," Warner said in a recent interview. "The country really needs this."

The Democrat's personal mission first began with a single Republican partner almost four years ago, grew to include more senators known as the "Gang of Six" and now has him acting as a provocateur of a larger, informal effort to build a Senate coalition that can pass what's been called a "grand bargain."

The goal: to slow the growth of the $16.8 trillion national debt through a combination of budget cuts, entitlement reforms and new revenue. Many elected leaders and experts say the debt, growing by the day as the government borrows hundreds of billions every year, is not sustainable and is stalling job creation.

Warner is hardly the only person in Washington pushing for a broad proposal, but many note that he has stood out as a relentless Senate voice pressing for a debt solution even as Congress and the White House have shifted their attention.

"He has been working this issue and pushing it onto the national stage," said Maya MacGuineas, president of the nonpartisan Committee for a Responsible Federal Budget.

The debt increasingly has become the centerpiece of debate over federal spending and taxes as President Barack Obama and leaders of the House and Senate say they want to find common ground. Sharp partisan differences over raising taxes or changing entitlement programs continue to stifle compromise.

"Everything I've said about this issue, I believe with all my heart," Warner said, adding that the slow pace has been frustrating. "You've got to plant a lot of seeds. And you've got to recognize that maybe things aren't moving as fast."

Warner contends that this year, there's more willingness - at least in the Senate - to look for an agreement.

Congress and the White House are "halfway there" because of efforts that include a late December deal to approve raising about $700 billion by repealing portions of the Bush tax cuts that affect wealthier Americans and the start, in March, of automatic budget cuts known as sequestration.

The nonpartisan Congressional Budget Office said the annual budget deficit is shrinking because of those changes and a small uptick in the economy that has increased tax revenue. The government, which has been borrowing about $1 trillion per year, is expected to borrow less in 2013 - about $845 billion, according to the CBO.

While it might be the smallest deficit since 2008, CBO analysts warn that without further action, the deficit will grow again because of the rising cost of health care and an aging population tapping into Social Security and Medicare.

Warner said stabilizing the debt will require at least three other actions that cut to the center of the debate over the role of government and how it pays for services.

The sequester has to be changed, he said, to more thoughtfully carry out the automatic cuts. At the same time, he said, entitlement programs, such as Social Security, Medicare and Medicaid, have to be adjusted to address fast-rising costs.

Another $600 billion to $900 billion in new revenue has to be raised to prevent cuts in education, transportation and defense, he said.

The sequester, which has required $85 billion in cuts this year - half in defense and half in domestic programs - has been unpopular because it mandates across-the-board trims. The cuts would continue for nine more years, totalling more than $1 trillion.

Many politicians argue that the sequester requirements need to be changed so that departments have more flexibility in making cuts, instead of applying them across all accounts.

The more difficult debate centers on finding new revenue and changing entitlements.

"I think the rub still is how you generate the revenues," Warner said. "At the end of the day, I think we can get to entitlement reforms."

However, it's important they deal with all the changes in one bill so that Republicans, who dislike increasing taxes, and Democrats, who want to protect entitlements, have taken the political risk together, he said.

To prod recalcitrant lawmakers to vote for a compromise, Warner said: "What I think this debate needs right now are a couple of new ideas. We're still going 'round and 'round in a circle on this stuff.... Let's assume that people have had a mindset change and they want to get to 'yes.' You almost need the new ideas just to be able to (answer), 'Why did you say yes now when you didn't say yes before?' "

Warner said he naively thought he could quickly build support for a deficit compromise after he and Sen. Bob Corker, a Tennessee Republican, found early success in drafting a key element of the Dodd-Frank bank reform legislation. In a chamber where members often can wait years for plum assignments, the first-term senators, both experienced in finance, were asked in 2009 to draft portions of the new law aimed at preventing banks from becoming "too big to fail" and requiring massive government bailouts.

"People came up and said, 'Oh God, Warner. That was remarkable,' " he said. "I'm thinking, 'This is what it's like to be senators.'... I didn't realize that was the exception - not the rule."

Warner, who is fond of aggressive pickup basketball, acknowledged that he's "been pretty obsessed that you've got to put points on the board from day one here."

With the 2014 election looming, he expects to introduce several bills this spring, including some that failed to get traction in past years. Among them: a proposed expansion of Medicare's hospice care for the terminally ill and more counseling regarding end-of-life-care decisions for elderly patients and their families.

The issue is a personal one for Warner, whose mother, Marjorie Warner, died in 2010 after a decade-long battle with Alzheimer's disease. He has spoken publicly about his family's frustration over not having talked with his mother about her wishes for medical care before the disease set in.

He's also part of a bipartisan group that is proposing establishing a federal infrastructure bank to help jump-start public works projects such as road or rail construction, pipelines or energy improvements. He estimates the $10 billion one-time federal investment in the bank could help leverage $500 billion in public-private projects.

As is expected of most Virginia federal legislators, he's deeply involved in attempts to safeguard the state's military installations and defense-related industries. He also serves on committees for banking, budget, intelligence and commerce.

His preoccupation has been trying to build consensus for confronting the national debt.

It started in the summer of 2009 with lengthy conversations with Sen. Saxby Chambliss, a conservative Georgia Republican, at a time when Democrats and Republicans were wary of publicly working together on economic issues. By January 2011, the pair focused on trying to build support for a broad plan based on the work of Obama's debt commission, which was led by former Sen. Alan Simpson of Wyoming and Erskine Bowles, White House chief of staff for Bill Clinton.

Warner and Chambliss favored reducing the debt's growth by $4 trillion over 10 years with a combination of deep spending cuts, reforms in Social Security and Medicaid, and revenue increases - including reducing or ending some popular tax deductions.

Their efforts helped spark the creation of the informal bipartisan senate group, known as the Gang of Six, which met privately for months trying to hammer out a plan that could be presented for a vote. However, the lawmakers couldn't agree on the details.

While the gang faded - its name shifted to label a separate "Gang of Eight" senators pushing for immigration reform - Warner did not back off. He continued speaking at public forums and hosting private Senate gatherings in his Alexandria home to provoke discussions of a grand bargain.

MacGuineas credits Warner's persistence with keeping alive the search for compromise when others kept quiet, saying, "There's been a leadership void that Mark Warner has filled for months, if not years."

His work also has been noticed by the White House. In recent months, as Obama began reaching out to GOP lawmakers and others for private meetings, the president sought Warner's advice about which Senate Republicans are open to compromise. Warner was among a dozen Democratic senators who attended a private two-hour dinner with Obama last month at the ornate Jefferson Hotel in Washington.

Warner, who has said he will seek a second term in 2014, shakes his head when asked whether he wants a Senate leadership position as a way to gain more influence.

"There are two paths that seem traditional paths. One is, you're here a long time. Or two, you become a part of the party leadership," he said, sipping a glass of Diet Coke in his suite in the Russell Senate Office building. "You know, we're trying a different way."

Warner said he turned down an offer to head the Democratic Senatorial Campaign Committee, which recruits and finances Senate candidates, because it hurts his ability to build compromises with Republicans.

He said he would have a hard time trying to sway a GOP senator to work with him while thinking to himself, "I'm spending all my time trying to recruit somebody to get you thrown out."

It's part of politics, he said, adding, "It's the way the rules are played, but it just didn't feel right to me."

Sen. Corker, a Republican, said the key to Warner's influence is his ease with people.

"He's a convener. He builds relationships," Corker said. "There are some people in the Senate that, candidly, are loners - that don't like being around others."

When asked about the odds of actually getting a bipartisan compromise given the rancor on Capitol Hill, Warner looked to the past.

"You're shaped by your prior experiences," he said. "When I was governor, the first year, I said I was going to do all this reaching out to Republicans in the General Assembly. In the House, I got burned almost every time. I got called naive, crazy. By year three and four, when we got a whole lot of stuff done, people weren't calling me as crazy."