Results from Rhode Island’s statewide election started coming in at 8 pm last November 6th. It didn’t take long for a local TV station to declare Democratic U.S. Senator Sheldon Whitehouse the winner over his Republican challenger, Robert Flanders.

“Like at 8:01,” recalled Whitehouse.

Whitehouse enjoyed a lopsided victory, with more than 61 percent of the vote, so the race was easy to call. Like most incumbents, Whitehouse had some big advantages. One of them was money.

Since his last election back in 2012, Whitehouse had raised more than $6 million. Flanders got into the race in November 2017, so he had a lot less time to seek contributions. The Republican raised a little more than $1 million, an amount dwarfed by Whitehouse’s campaign account.

“He was able to effectively out-spend me five or six to one, particularly with television ads, which are so important in a statewide race,” Flanders said.

Some Republicans had high hopes for Flanders’ challenge to Whitehouse. Flanders is a high-profile lawyer and former Rhode Island Supreme Court justice. During his campaign, he accused Whitehouse of being an out-of-touch elitist. But with millions more in his campaign account, Whitehouse dominated the TV airwaves with messages condemning President Trump’s tax cut and congressional Republicans.

“They’re going to take the trillions of dollars they gave to the wealthiest Americans and they’re going to pull it out of the healthcare of regular Americans,” Whitehouse said in one commercial. “There is no way I’m going to let that happen.”

Congressional incumbents generally win re-election more than 90 percent of the time, and Whitehouse is unapologetic about his aggressive fundraising. Whitehouse says spending more than $5 million on his re-election was part of what it took to show Rhode Islanders that he wanted their votes.

“And even if you had no opponent, they would want to see a big effort,” he said. “They’d want to see you talking to them on television, they’d want to see your mail in their mail slots, they’d want to see you out there hustling.”   

Spending in the most expensive U.S. Senate race last year – between Texas Sen. Ted Cruz, a Republican, and Democratic challenger Beto O’Rourke -- topped $100 million last year.   

But Brown University political science professor Wendy Schiller said incumbent senators from small states like Whitehouse rarely spend so heavily to win re-election. (Whitehouse, however, spent a comparable amount -- $5.2 million -- during his 2012 re-election campaign against a lesser-known GOP opponent, Barry Hinckley.)

“What’s extraordinary about Sheldon Whitehouse is that he spent that much money in a very small state,” Schiller said. “So it was either overly cautionary on his part, or he was scared of something in that race, because the number is large for the size of the state and the fact that it was his second re-election campaign.”

The thing that concerned Whitehouse was a potential attack fueled by millions of dollars in dark money from powerful hidden interests. Dark money comes from shell corporations, donors’ trusts and charitable entities.

“If there’s a person in the Senate who the fossil fuel industry and the big dark money crowd is more annoyed with than me, I don’t know who that person is,” Whitehouse said. “So I viewed myself as being very high up that target list.”

Dark money has been around since the 1970s. But the amount of dark money in U.S. elections exploded after 2010. That was when the Supreme Court’s Citizens United decision lifted restrictions on campaign spending by unions, nonprofits and businesses. None of these groups need to disclose their contributors, and they can make unlimited independent expenditures to influence the outcome of elections.

Because of this, Whitehouse said, he needed a big pile of campaign money as a form of self-defense. The watchdog group the Center for Responsive Politics says the top industries contributing to Whitehouse since 2013 include law firms, retirees, and the finance sector.

Whitehouse remains an outspoken critic of some kinds of campaign spending. His book, “Captured: the Corporate Infiltration of American Democracy,” was just published in paperback. In a note, Whitehouse said he wrote the book based on his experience in the Senate "and thinking a lot about why so many Americans are so disaffected," and how progress gets blocked.

A super PAC called RIMF raised about $180,000 and spent most of that on TV ads in support of Flanders’ campaign toward the end of the 2018 campaign season. The group attracted contributions from deep-pocketed individuals, including $50,000 from former Hasbro chairman and CEO Alan Hassenfeld.

But as it turned out, dark money interests did not come after Whitehouse last year.

Schiller, the Brown University professor, said the Citizens United decision has left a relatively even playing field for Democrats and Republicans.

“The Democrats have gained much more parity with the Republicans in their capacity to raise and spend money,” she said. “The tech industry tends to be liberal and more Democratic than they are Republicans, so they manage to find sources to raise a lot of money to be competitive with the Republicans.”

But Whitehouse said Citizens United fundamentally changed the rules of American politics.

“Once you let big special interests spend unlimited money, you necessarily give them the power to threaten to spend that same unlimited money,” he said. “And it’s cheaper and it’s easier to get on the phone to a candidate and say, ‘it’s your ass if you dare cross us on this and you know we’re serious, because we can spend $10 million in the next primary against you, and so, are you going to behave?’ ”

Whitehouse said it’s often easier for candidates to behave, “and then you never see the $10 million spend. You’ve just fixed the deal secretly and behind the scenes.”

The influence of dark money seems unlikely to fade any time soon. Whitehouse has a proposal called the DISCLOSE Act that would require contributors to be identified for any federal campaign expenditure of more than $10,000. But he’s introduced the DISCLOSE Act every year since 2012, and it has yet to become law.

This is an expanded version of a story airing on The Public's Radio.