Wearing a charcoal suit as disordered as the white hair encircling his head, and flanked by just two aides as he walked to the podium, Vermont independent Bernie Sanders laid out his motivation for seeking the Democratic Party's nomination Thursday before an audience of about 100 reporters, camera operators, aides, and onlookers (including one man who wore a hemp ballcap).

Workers are toiling more hours for low wages, while 99 percent of new income goes to the top 1 percent, he said.

"That type of economy is not only immoral, it is not only wrong," Sanders said, speaking without notes. "It is unsustainable."

He sounded passionate, progressive, and populist. He also sounded a lot like Hillary Clinton. And therein lies the rub for the long shot of all long shots: a senator who takes his business in Washington seriously but is unwilling to wear the label of a party he hopes to represent in the 2016 general election.

I'm an independent, he insisted when asked whether he was a Democrat.

That's why Sanders is the only politician who could get away with announcing an outsider's campaign for president from the shadow of the Capitol Dome on a grassy plain called the "Senate swamp."

His fans hope that he can pull off the unlikeliest of upsets. And Sanders said he's undaunted by the odds, having won 71 percent of the vote in his last reelection after once losing a statewide race with 1 percent of the vote.

But Clinton's move to the left has the effect of crowding out longtime liberal stalwarts who occupy space similar to Sanders's on the political spectrum. Most, like Senator Elizabeth Warren of Massachusetts, have passed on running against her, knowing they can hold her feet to the fire from the sidelines and that they stand little chance of defeating her juggernaut.

To the left, to the left

The issues Sanders identified as his causes in this campaign — economic justice, climate change, and reining in the influence of big spenders in politics and government — are all now standard fare for the much better funded, much better known, and much more big-D "Democratic" Clinton.

She noted as much on Twitter Thursday, and Sanders responded in kind:

Thanks @HillaryClinton. Looking forward to debating the big issues: income inequality, climate change & getting big money out of politics. — Bernie Sanders (@BernieSanders) April 30, 2015

Clinton spoke of cycles of poverty and inequality just yesterday in a speech on criminal justice reform at Columbia University.

"Our goal must truly be inclusive and lasting prosperity that’s measured by how many families get ahead and stay ahead, how many children climb out of poverty and stay out of prison, how many young people can go to college without breaking the bank, how many new immigrants can start small businesses, how many parents can get good jobs that allow them to balance the demands of work and family," she said.

Like Sanders, Clinton has mocked climate-science deniers and has made campaign finance reform a pillar of her agenda in this campaign — even as she solicits money from megadonors such as Ambassador Elizabeth Frawley Bagley, a longtime ally who was scheduled to host one of three fundraisers for Clinton in Washington on Thursday.

That's not to say there's less than a dime's worth of difference between Clinton and Sanders. They have had substantive differences in the past, and no amount of shading will ever make her the instinctive populist that he has been for decades.

The differences

Many years ago, Clinton was a middle-class kid in the Chicago suburbs. She has since become a jet-set multimillionaire former first lady and presidential nomination frontrunner. There has been a bubble around her for a long time, which is why her comments about leaving the White House "dead broke" were mercilessly ridiculed. Her home in Washington is on Embassy Row and would probably sell for more than $4 million.

Unlike Clinton and the vast majority of his Senate colleagues, Sanders has parlayed his career in public service into a lifestyle that is less than lavish. He makes $174,000, a salary frozen since 2009. He lives in a narrow, two-floor, one-bedroom townhouse on Capitol Hill that he bought (from me) for less than $500,000. There's a window air-conditioning unit on the second floor because the 125-year-old home doesn't have central air. It's worth the price of a mansion in Iowa or New Hampshire or Vermont, but it's modest for a walk-to-work crash pad a few blocks from the Senate.

His net worth, based on disclosed ranges, is somewhere between $110,000 and $551,000, according to the Center for Responsive Politics. He has debts of up to $65,000 or so. If he gave three or four Clinton speeches, he could retire. Not that he would do either. Sanders said Thursday that he grew up poor, that his father dropped out of high school, and that his brother introduced him to books, of which there were not a lot around the Sanders household.

Their personal finances and economic backgrounds will matter in some Democratic circles. Clinton's shift toward populism doesn't feel authentic to party progressives who have watched her and her husband buck-rake from billionaires to boost their campaigns, their foundation, and their own personal fortune.

Sanders is proud that he's never run a negative ad; Clinton made her 2008 campaign about tearing down Barack Obama as unprepared for the presidency. It's unimaginable that Sanders could beat Clinton without hammering the differences between them on substance. And he said Thursday that it is important to define those differences.

"I voted against the war in Iraq"

At first, Sanders seemed uneasy about taking on Clinton directly.

"It's too early," he started to say when asked where he differed from Clinton on policy. "We don't know what Hillary's stances are."

Then, he acceded.

"I voted against the war in Iraq," he said of the 2002 roll call that helped sink Clinton's 2008 candidacy. He spoke of his leadership against the Trans-Pacific Partnership trade deal, which Clinton's State Department team worked on and which she has tried to give herself wiggle room on in recent weeks. And he talked about his fervent opposition to the Keystone XL pipeline, about which Clinton has always been studiously quiet — because of or despite — the lead role the State Department played in reviewing the project when she was in the State Department.

It's not at all clear that any of those issues will be dispositive in a Democratic primary. While Clinton's comfort with the use of military force is a mismatch for a Democratic Party base that abhorred both Vietnam and Iraq, the latter war is less of a political issue now than it was when a full complement of American soldiers were in the Middle East.

Democrats worry about a return to Clinton-style trade deals such as NAFTA that they believe rob American workers to the benefit of multinational corporations. But Clinton hasn't come down firmly on TPP, and NAFTA, despite hurting many other Democrats, did little damage to Bill Clinton in his 1996 run to reelection. And the most prominent opponent of the Keystone pipeline, billionaire Tom Steyer, is a longtime Clinton ally, contributor, and fundraiser.

Running to win

Before Sanders's 10-minute press conference, reporters milled around the Senate swamp and joked about how it would be the biggest crowd of journalists Sanders had ever attracted to an event. When Sanders walked up, with a rolled up piece of paper in his hand, he had to navigate around the cameras to take his place at the podium. He seemed a little surprised by the attention.

"Thank you," he said into a microphone, recoiling a bit from the electric sound of his own voice and issuing a quick "Whoa!"

Save for the unusually large audience for him, Sanders's announcement was understated as presidential kickoffs go. He might well have been announcing the introduction of a dairy amendment to the farm bill from a location so close to the Senate floor that he closed the press conference by saying he had to get back to work and then walking a couple of hundred feet to the Capitol.

There are some who believe Sanders is running to make a point, to elevate the issues he cares about. Others debate whether his entry will force Clinton to move to the left on issues in a way that hurts her in a general election or will give her a point against which to triangulate and present herself as more moderate in November 2016.

But Sanders's entry isn't likely to have much effect on Clinton because they already sound so much alike.

When she launched her 2008 campaign, Clinton famously said, "I'm in, and I'm in to win."

Asked Thursday whether he was running for the sake of the issues he cares about, rather than as a serious candidate for the nomination, Sanders, sounding a lot like Clinton, rejected that construct.

"We're in this race to win," he said.