Senator Bernie Sanders (I-Vt.), the idiosyncratic, crusty 73-year-old, has entered the race for the Democratic presidential nomination, the first challenger to prohibitive favorite former Secretary of State Hillary Clinton. He could have a profound influence far beyond the votes he garners.

Sanders is a funhouse mirror image of Clinton. She has universal name recognition (by her first name), unlimited funds, national campaign experience and a powerhouse political operation. He has scant name recognition, paltry funds, no national campaign experience and hasn’t begun to build a campaign staff. With a net-worth ranking among the lowest in the Senate, Sanders can be an authentic populist — the real deal. As one supporter said, he is the candidate of the “12-hour filibuster and the $12 haircut.”

Sanders’s announcement was treated with respect by a press corps eager for any kind of race on the Democratic side. Pundits dismiss his chances in part because Clinton is expected to raise a billion dollars or more for her campaign. Sanders hopes to raise $50 million.

But Sanders is likely to do far more than exceed low expectations. His candidacy could have a dramatic effect in building an already growing populist movement inside and outside the Democratic Party.

As Sanders made clear in his announcement, his focus will be on the central challenges facing this country: an economy that does not work for the vast majority of its citizens and a politics corrupted by big money and entrenched interests.

Sanders refuses to take part in politicians’ usual, incessant pursuit of large donations. So he is a political rarity: Someone free to speak forcefully to the often insidious connection between the two.

The economy serves only the few, he contends, because the 1 percent have used their resources to rig the rules in their favor. Big money in U.S. politics — in both elections and lobbying — isn’t only about the whims of billionaires or the free speech of corporations. It is also about fixing the game so that the rewards of economic growth are captured by very few.

This reality of the 1 percent, and the 1 percent of the 1 percent, sets up Sanders’ populist agenda. He talks about getting big money out of politics and making voting easy rather than hard. About fair taxes on the rich and corporations to invest in rebuilding America and addressing the danger that is climate change. About balancing U.S. trade and rejecting any more trade deals that look like they were designed by and for multinational corporations. About breaking up the big banks and curbing destabilizing speculation.

The continuing economic woes of the middle class are his key focus. He wants to: provide debt-free college for all who seek it; guarantee workers a living wage and such basic rights as paid-sick days and equal pay; expand Social Security benefits, and move to Medicare for all.

Sanders has argued this case for some time. But this could be his moment. Sixty percent of Americans agree with him that the “economic system unfairly favors the rich,” which may be one reason politicians in both parties are uncomfortably trying to fit into populist garb. Two-thirds of the American public think the rich pay too little in taxes. Two-thirds think CEO pay is too high. Three of four think climate change is a serious or very serious matter. In the 24 hours after he declared, he raised $1.5 million. Roughly 35,000 donors gave, on average, less than $50. A larger group of 145,000 signed up online to volunteer.

Sanders’ argument is now echoed by influential political leaders and movements inside and outside the Democratic Party. Senator Elizabeth Warren (D-Mass.) has struck the deepest chord, but she is not alone. Senators Sherrod Brown (D-Ohio), Jeff Merkeley (D-Ore.), Sheldon Whitehouse (D-R.I.) and Tammy Baldwin (D-Wis.) are also taking leading roles. The Congressional Progressive Caucus, increasingly forceful under the leadership of Representatives Keith Ellison (D-Minn.) and Raul Grijalva (D-Ariz.), is now the largest and most influential caucus in the House Democratic Party.

Across the country, activists from online operations such as MoveOn and Credo and from on-the-ground groups such as the National People’s Action and the Center for Popular Democracy are joining labor unions, environmentalists, women’s organizations and clean-government groups in a growing insurgent chorus.

Sanders’ populist policies also have been gaining traction in elite intellectual and policy circles. When Wall Street’s excesses blew up the economy in 2008, the consensus on the benefits of unfettered free markets shattered. Leading economists, including Nobel prize-winners Paul Krugman and Joseph Stiglitz, now admit that U.S. trade policies have contributed to inequality, which has undermined wages at home. Former Treasury Secretary Lawrence Summers warns about a costly and debilitating deficit in public investment.

The International Monetary Fund and Wall Street graybeard Robert Rubin, who was Treasury secretary in the Clinton administration, agree that the decline of unions has contributed to growing inequality. More and more investors warn that warped chief-executive pay schemes lead to wrongheaded corporate policies. Sanford Weill, former chief executive and chairman of Citigroup, supports breaking up the big banks. Climate change is viewed as a growing cost on public and private balance sheets. Parents across the political spectrum are standing up for public education.

This backdrop will propel the Sanders challenge. Between now and the February 2016 New Hampshire primary, he will be arguing a case that the public experiences, is echoed by other political leaders and receives weight from policy elites.

He’s likely to have a strong start. Iowa and New Hampshire, the first contested states, feature the kind of retail politics – the town meeting, county fair and house party — that Sanders has practiced all his life.

Iowa Democrats harbor antiwar sentiments, which cost Clinton big in 2008 and will likely weigh against her again, as she is likely to brandish a more bellicose stance than President Barack Obama. The most potent on-the-ground political operation in Iowa has been built by the “Run Warren Run” group, activists pushing to get Warren into the race. It has an independent organizer for every caucus district and could easily switch their support to Sanders.

New Hampshire, meanwhile, is adjacent to Vermont. A decent portion of the state’s Democrats are familiar with Sanders and his politics.

None of this should suggest that Sanders can sweep to the nomination. After the first two states, the going gets tough for him. Sanders lacks the relationships with gatekeepers in the black and Latino communities that grow more important in the race, starting in South Carolina and Nevada. Without significant resources, it is difficult to gain name recognition, much less persuade voters that Sanders’ challenge is plausible.

The right, though enjoying any bite Sanders takes out of Clinton, is already baiting his “socialism.” Still, Clinton seems to be adopting a more populist tone and will likely champion bolder reforms, both to rouse the Democratic base and to forge a reform majority.

But however limited his run, Sanders will have months to be a credible candidate delivering a powerful message in a big megaphone to millions of Americans: The game is rigged to favor the few. There are alternatives. But only if people mobilize and take back their democracy.

The Sanders campaign will give thousands of organizers campaign experience. Like George McGovern’s 1972 campaign, it is likely to open opportunities for young candidates supporting his message to challenge the centrists within the party. It will help educate activists and inform citizens about what could be possible. He’ll attract thousands of donors and collect millions of contacts that could form the basis for continued political action.

In a populist moment, an authentic populist tribune may help build a movement that can transform America’s politics.