Senator Bernie Sanders is running for president with one goal in mind. It's not the White House, it's turning the spotlight on secretive political donations and the corporate giants who bankroll elections. John Barron writes.

Senator Bernie Sanders is running for president of the United States of America - an office he has absolutely no chance of winning.

No chance. None. Nada. Zip.

Sanders is Jewish, and while a Jew has never been elected president, that's not the reason he won't be elected in 2016.

And it's not because Sanders is seeking the nomination of the Democratic Party, which is almost certain to endorse Hillary Clinton. It's not even because he's not actually a member of the Democratic Party. Or the fact that he calls himself a "socialist" in a nation where that particular word is used as a criticism of incumbent Barack Obama. And no, it's not because Sanders comes from the tiny north-eastern state of Vermont with a population of less than 650,000 giving him a small popular base.

And it's not even because he's already three years older than the oldest-ever person elected president of the United States, Ronald Reagan, who was just 17 days short of his 70th birthday when he took the oath of office in 1981.

None of those things help, mind you ... but it's not the main reason he won't be elected president.

Sanders won't be elected president of the United States because despite his appeal to voters on the left wing of the Democratic Party, he is unlikely to raise a nickel from the people who really bankroll elections - Wall Street and Silicon Valley.

For all the talk of Obama's five million "mum and dad" grassroots donors chipping in $5 and $10 in 2008, propelling him into office on the back of a billion dollar war chest, corporate "bundlers" who gathered together piles of $2500 cheques from hundreds of their colleagues at investment banks and tech giants were still a huge part of his success.

According to the non-partisan Centre for Responsive Politics, Obama raked in more than $1 million from Goldman Sachs employees, about $850,000 from workers at JP Morgan Chase & Co, and more than $750,000 from Citigroup. Microsoft employees ponied up more than $850,000, Google about $820,000 and IBM just over half a million dollars.

And as candidates and campaign insiders have told me, workers at some major firms also know that if they write a cheque to a particular candidate, they are likely to see the same amount or more added to their annual Christmas bonus - just one of the gaping loopholes used to get around campaign finance restrictions.

Since Obama was first elected it has become even easier for business interests and wealthy individuals to shovel massive amounts of money into campaign coffers. The landmark 2010 "Citizens United" Supreme Court ruling determined that corporations were effectively people and their money was a form of speech and could therefore not be restricted. The "Super-PAC" (Political Action Committee) was born.

Sanders has pledged not to take money from Super PACs*. His biggest donors between 2009-2014 were retirees, who sent him cheques totalling just over $550,000, followed by Democrats and Liberals who gave $251,000 and Public Sector Unions who donated $120,000, slightly more than the contributions of lawyers and law firms.

So, you might well be wondering, why is this small state socialist senator running for president? It's for the very reason that he can't win that Sanders has decided to run. He wants to campaign on the issue of campaign finance reform. He wants to strip PACs of their influence, he wants to strip Wall Street and Silicon Valley of their influence. In short, he wants the impossible.

Still, by senator Sanders simply announcing he is running for president and getting his name on ballots that will decide who will be the Democratic nominee he gains a bully pulpit that money can't buy. It gets him free media coverage, and potentially a podium alongside Hillary Clinton and other Democrat hopefuls on debate stages across the country, which will be watched by millions.

Unlike other potential Democratic contenders such as former Maryland governor Martin O'Malley, former senator Jim Webb of Virginia, or vice-president Joe Biden, Sanders isn't even running as a fallback option in the event that Hillary's seemingly unstoppable march towards the nomination is tripped up by some tawdry Clintonesque scandal involving corporate or international donations to the family foundation, her deleted emails or Bill's penchant for interns.

No, Sanders isn't going to be elected president, but Democrats would do well to take him seriously. We don't yet know the extent to which he will be able to shape the debate, or force other Democrats to renounce secretive "Super PAC" money or put limits on corporate influence.

Sanders is running to raise important questions: who pays for American politics and what do they get in return?

*Editor's Note: An earlier version of this article said that Sanders refuses support from all PACs, when in fact he has only refused support from Super PACs. The Drum regrets this error.

John Barron is an ABC journalist, host of Planet America, and research associate at the United States Studies Centre at the University of Sydney.