How many billionaires support the Democratic vs. Republican parties?

Recently, Senate Majority Leader Harry Reid, D-Nev., has been on a crusade against what he believes is undue influence from wealthy individuals and corporations in campaigns, enabled in part by Supreme Court decisions in the Citizens United and McCutcheon cases.

A reader pointed us to one of Reid’s latest comments on the subject from the Senate floor.

"The decisions by the Supreme Court have left the American people with a status quo in which one side's billionaires are pitted against the other side's billionaires, except one side doesn't have many billionaires," he said in a floor speech.

This comment quickly prompted the Republican National Committee to circulate a YouTube video of Reid’s comment, with the mock-incredulous headline, "Harry Reid Claims Democrats Don't Have Billionaire Backers."

At first, we thought Reid said, "one side doesn’t have any billionaires" -- as did some critics on social media. If he had said "any," that would have been a false statement. But a close listening shows that Reid said "many."

That makes our job harder -- how many of America’s 492 billionaires do you need to have the backing of "many" billionaires? And do Democrats have fewer than Republicans?

We can’t answer the question of which side has more because it’s impossible to know exactly who donates to elections and how much they give. Certain types of political nonprofits are not required to disclose all their funders, although some do so voluntarily.

For example, despite being Reid’s biggest rhetorical targets, brothers David and Charles Koch do not appear as donors on any of the campaign finance information we reviewed. The two businessmen co-founded Americans for Prosperity, an influential conservative super PAC.

But by looking at some publicly available information -- mostly from the Center for Responsive Politics’ Open Secrets database, which collects disclosure data from the Federal Election Commission -- we were able to get an idea of what role America’s billionaires play in each party.

We cross-checked the Open Secrets list of the top 100 individuals donating to outside spending groups in the current election against the Forbes list of the world’s billionaires and found that, as of June 19, there were 22 individuals on the Open Secrets list who were billionaires. Of those 22 billionaires, 13 -- or more than half -- gave predominantly to liberal groups or groups affiliated with the Democratic Party. The other nine gave predominantly to conservative groups. (A list of billionaires and how much they donated can be found here.)

Among the liberal-leaning donors are former New York City Mayor Michael Bloomberg and business magnate George Soros. On the conservative side are S. Daniel Abraham, who founded SlimFast, and Vincent McMahon, who owns World Wrestling Entertainment.

These lists aren't complete due to the disclosure rules protecting donors' identities. Both sides are spending more of this "dark money" than ever before, said Robert Maguire, a political nonprofit investigator at the Center for Responsive Politics.

Still, from what we know about this cycle, the Democrats do have significant billionaire backing. The top donor from either party so far this cycle is pro-Democratic -- California billionaire Tom Steyer, who has given more than $11 million and has pledged to spend at last $50 million. His group, NextGen Climate, plans to attack Republican candidates in several competitive races on climate change. Some have called Steyer’s initiative a liberal answer to the Koch brothers.

In other recent election cycles, though, Republicans have had the upper hand.

According to Open Secrets, Republicans had a larger share of the billionaires -- and their contributions to outside spending groups -- in the 2012 election cycle. Among the top 100 donors in the Open Secrets list, 33 were billionaires, and of those, 14 gave primarily to liberal groups while 19 gave to conservative groups.

In addition, the top 100 donors of 2012 gave 41 percent of all the money collected by outside spending groups, and of their donations, 71 percent went to conservative groups.

Some of the leading Republican-oriented donors were Jon Huntsman, Sr., father of the 2012 Republican presidential hopeful; Richard and Bill Marriott of the hotel chain; and casino mogul Sheldon Adelson. Adelson topped the list at more than $90 million in donations -- three times what the next top donor gave.

The Republican advantage in 2012 is even more visible in a Forbes list of the top 40 billionaire backers on each side -- including more than just those who donated to outside spending groups, such as direct campaign donations or those who fundraise for a candidate. Of those 40, 29 supported conservative groups and candidates, and just 11 supported liberals.

Republicans tend to donate to and use non-disclosing groups more than Democrats do, said Center for Responsive Politics spokeswoman Viveca Novak. Conservative political nonprofits spent almost five times as much as liberal ones in 2012, according to Open Secrets data. So far in 2014, they have spent almost twice as much.

That said, there were some notable liberal billionaire donors in 2012, as well, including filmmaker Steven Spielberg and LinkedIn co-founder Reid Hoffman.

Also, neither party is pleading poverty these days due to funds raised from people below the billionaire bracket. So far in the 2014 election cycle, the top Democratic Party committees have raised more than $725 million, according to Open Secrets. The top Republican Party committees have raised more than $600 million. In the 2012 election, the Democrats and Republicans each raised about $1.7 billion.

Democrats may have closed the gap this cycle by getting more support from the growing number of young, ultra-wealthy liberals in Silicon Valley -- like Hoffman, who is worth $3.2 billion at 47 years old -- suggested Forbes reporter Clare O’Connor, who has covered the subject. At the same time, an increasing number of the very rich are splitting their support between the parties, she said.

We can’t make a final call on whether or not Reid was right in saying the Democratic Party "doesn't have many billionaires." We know that both parties have billionaire backers. In 2012, the advantage went to the Republicans. So far in 2014, the Democrats have the edge in terms of public donations to outside spending groups. But this is far from a full picture because of current donation disclosure rules.

"We’ll never know," O’Connor said.