Washington (CNN) -- It's been widely reported. The Republican Party is locked in battle. Establishment Republicans are being challenged by insurgents hoping to purify the brand and return the GOP to small government, free market principles.
The conservative grassroots are organizing this election season to elect their preferred, ideologically pure candidate, even if that means unseating House and Senate incumbents. It's a strategy they had in 2010 and 2012 with mixed results.
But too much emphasis might be placed on the internal strife. Because if money has anything to do with it, which it does, the battle is more like a fight between David and Goliath.
The three main groups working to unseat a handful of incumbents are the Senate Conservatives Fund, Club for Growth and FreedomWorks. A few of the incumbents they want to unseat: Sens. Mitch McConnell of Kentucky, the chamber's Republican leader, and Thad Cochran of Mississippi. Also on their list is Rep. Mike Simpson of Idaho.
They have raised a nice chunk of cash. Combined, the groups' super PACs, which have different agendas and are only being lumped together because of their influence and effectiveness and their ability to raise unlimited amounts of campaign cash, have spent about $15 million in the past 15 months.
That's not an insignificant amount and that's a good portion of the nearly $50 million spent by all outside groups combined this midterm election season.
But Robert Maguire of the Center for Responsive Politics said campaign spending is already ahead of this point in 2012, the most expensive campaign season in history.
"No matter of how you look at it, we're well ahead of where we were at the last midterms and also the last election," he said.
But the thing is that the incumbents they are trying to beat are raising even more cash. Political strategists agree that incumbents are much more prepared this time around.
For instance, McConnell has amassed a war chest of $20 million and he's already spent $10 million -- that's almost more than the three groups combined - for his May 20 primary.
And those groups are involved in a dozen different races. Making it that much more difficult in the money race is that McConnell's cash doesn't include the outside groups that support him.
"Sometimes we can compete against them and sometimes we can't," Russ Walker, the National Political Director of FreedomWorks For America, said. "Sometimes we win and sometimes we don't."
While McConnell has raised and spent an enormous amount so far -- more than any other candidate, Republican incumbents with more modest resources are still operating at an advantage.
Of all the incumbents being challenged, Cochran is expected to be in the most danger of losing. He is currently winning the cash contest, however.
He and the flushest super PAC backing him have spent about $2.6 million ahead of the June 3 primary. His challenger, Chris McDaniel, and the groups backing him have spent about $1.7 million.
And in Idaho, where Rep. Mike Simpson is facing off against Bryan Smith, Simpson has spent more than $1 million while Smith, who has received the endorsements of many non-establishment groups, has spent only $550,000 for their May 20 primary.
People who financially back efforts to oust incumbents they consider unfit believe their money is well-placed, even if their candidate doesn't win.
Walker refers to McConnell's race: "He's going to spend $10 to $15 million in this primary convincing the voters he's the person we want him to be. His voting record has become more conservative. His rhetoric has become more fiscally conservative. In my mind that's a win."
Incumbents have built-in advantages. Senators have a six year campaign cycle and raise money for their next election for all six years. In addition, they often have access to the established network of party donors and influence peddlers.
Many independent groups, such as the super PACs and 501c4s, didn't even exist in 2010 when the Supreme Court opened the flood gates to independent spending with the Citizens United decision. But they are learning quickly and each campaign season the top groups raise more.
Maguire said the influx of cash into campaigns has adverse consequences. "It's basically become the permanent campaign," he said.
CNN"s Robert Yoon contributed to this story.