Republican activist Shaun McCutcheon walks past the Capitol as he leaves the Supreme Court in Washington on Oct. 8, 2013. His case has further amplified the influence of the wealthy on campaigns. (Susan Walsh/AP)

Andrew Sabin gave Republicans so much money in 2012 that he accidentally went over a limit on how much individuals could donate to federal candidates and party committees.

So Sabin, who owns a New York-based precious-metals refining business, was delighted when the Supreme Court did away with the limit in April. Since then, he has been doling out contributions to congressional candidates across the country — in Colorado, Texas, Iowa and “even Alaska,” he said.

Top Republicans have taken notice: Sen. Ted Cruz (Tex.) and Florida Gov. Rick Scott have paid him personal visits this year, he noted proudly.

“You have to realize, when you start contributing to all these guys, they give you access to meet them and talk about your issues,” said Sabin, who has given away more than $177,000. “They know that I’m a big supporter.”

Sabin and other wealthy political contributors have more access than ever to candidates since the ruling in McCutcheon v. Federal Election Commission. More than 300 donors have seized the opportunity, writing checks at such a furious pace that they have exceeded the old limit of $123,200 for this election cycle, according to campaign finance data provided by the Center for Responsive Politics, a nonpartisan research organization.

Among them are Las Vegas casino titans and New York hedge fund managers, Silicon Valley investors and Texas oil barons. Their ranks include well-known billionaires such as George Soros, Sheldon Adelson, and Charles and David Koch, but also lower-profile players such as Arkansas poultry magnate Ronald Cameron and New York pearl purveyor Christina Lang Assael.

Together, 310 donors gave a combined $11.6 million more by this summer than would have been allowed before the ruling. Their contributions favored Republican candidates and committees over Democratic ones by 2 to 1.

The data provides the most comprehensive picture of the immediate fallout of McCutcheon, a case brought by an Alabama businessman and the Republican National Committee that has further amplified the influence of the wealthy on campaigns.

As soon as the Supreme Court issued its opinion on April 2, major political donors who had maxed out jumped to take advantage, doling out $1.8 million more by the end of that month, according to a Washington Post analysis.

The expanding reach of mega-donors has fueled criticism that the political system increasingly favors the rich, an issue that Democrats have sought to make central to this year’s midterm elections.

But many wealthy donors rejected the notion that the playing field is tilted in their favor.

“Baloney,” said Stanley Hubbard, a Minnesota media mogul who largely backs Republicans and conservatives. “The average person can get their friends together and raise small donations that amount to big donations.”

Hubbard, who has given more than $191,000 directly to candidates and party committees this election cycle, said that since the limit on total donations was lifted, he fields incessant political solicitations.

“My phone rings, rings, rings,” he said. “It’s made me poorer, I’ll tell you that, but it’s made it possible for me do a better job as a citizen. It used to be kind of nice to say, ‘I’m maxed out,’ but I really believe that people running for office need to have support.”

The McCutcheon ruling did not do away with base limits on how much individuals can give a single candidate — currently $5,200 per cycle — or to parties, now $32,400 per year. But the decision threw out the overall limits on how much donors could give to federal political committees in a two-year election cycle. The amount had been set at $123,200 for this year’s midterms, including $48,600 to candidates, and $74,600 to parties and traditional political action committees.

“What happened before was you couldn’t give the max to a lot of good friends,” said John Catsimatidis, a New York supermarket mogul and one-time Republican mayoral candidate. “Now you have no excuse.”

He praised the court’s decision, saying that labor unions already had the ability to spend unlimited sums on behalf of candidates. “People want to put a restriction on people who do well in our country,” Catsimatidis said.

The McCutcheon ruling is not expected to have as dramatic an impact as the 2010 Citizens United case, which paved the way for the creation of big-money super PACs that now dominate the political landscape.

Even though the additional millions flowing to candidates and parties “is real money, in the grand scheme of our campaign finance system, it’s background noise,” said Robert Kelner, a Washington campaign finance lawyer.

But for individuals who can afford to give to dozens of campaigns, the new freedom offers yet another lever of influence.

Sabin said he has used his expanded access to politicians to press Republicans to be more environmentally conscious.

“My issues are not selfish issues,” he said. “I want to leave my kids and grandkids a healthy planet.”

Donors who have exceeded the pre-McCutcheon limit have given at least $50.2 million to candidates, parties and traditional PACs, according to FEC data provided by the Center for Responsive Politics, which includes contributions made through June as well as some in July. (The total does not include any money donors gave to super PACs, which can accept unlimited money and were not counted toward the previous limit.)

Of that amount, $33.3 million went to GOP candidates and political committees and $15.6 million went to Democrats.

There has not been a flood of donations to new supersize joint fundraising committees Republicans have set up to collect big checks from donors. The Democratic Senatorial Campaign Committee also created one in August.

A large portion of the contributions by those who have taken advantage of the McCutcheon ruling — nearly $16 million — has gone directly to candidates. Such donations allow them to have a greater impact, several contributors said, because candidates can purchase television advertising at the lowest rate available.

One donor, who spoke on the condition of anonymity to avoid being further targeted by political fundraisers, said he has written checks to 39 PACs, 25 Senate candidates and 16 House candidates this year.

Roy Pfautch, an international public affairs consultant and GOP donor based in St. Louis, said he is giving candidates far more than he could have before. Out of the $165,800 he has donated, $96,000 has gone directly to them.

“I think it’s a very wise stewardship of the money, because they know what their needs are,” he said.

Before the McCutcheon decision, just a tiny cadre of political donors was bumping against the limit. In 2012, 646 gave the maximum of $117,000 for that election cycle, according to an analysis by the Center for Responsive Politics. Together, they donated more than $93 million directly to federal candidates and political committees.

This year, mega-donors on the right such as San Francisco investment company executive Charles Schwab, wrestling executive and one-time Senate candidate Linda McMahon, casino magnate Steve Wynn and hedge fund manager Paul Singer have taken advantage of the change. On the left, prolific check writers include Chicago media executive Fred Eychaner, angel investor Ron Conway, Maryland tech entrepreneur Frank Islam and Paul Egerman, a software entrepreneur in Weston, Mass.

“It’s no surprise that the largest donors are the first ones to take advantage of McCutcheon, because they were already players,” Kelner said. “But I think what we will eventually see is newcomers to the political world gradually taking advantage of the ability to give much larger figures.”

That thrills Shaun McCutcheon, the chief executive of an Alabama electrical engineering firm who brought the Supreme Court case and pronounced himself “tickled” by the results.

“I would think everybody would be for more money in politics like I am, because we’re just spreading speech,” he said.

McCutcheon has not exceeded the former $123,200 limit — although he said that with recent donations, he has given more to candidates than would have been allowed previously.

In the coming months, “I’ll support a lot more candidates,” he said. “I’ll make sure I get there.”