According to speculation on the internet, Rush Limbaugh may be implicated in voter fraud by an investigation on illegal voting in the March 4, 2008, Ohio Democratic Primary. During and after the primary election, some sources were reporting thousands of Republicans "crossing over" and registering as Democrats, to vote for Hillary Clinton. Starting February 19, on his radio show and elsewhere, Limbaugh had repeatedly urged Republican voters in both Ohio and Texas to vote for Clinton. He dubbed the effort Operation Chaos, explaining that the longer the fight between Clinton and Obama, the better for Republicans in the general election. After Clinton won both the Ohio and Texas primaries, Limbaugh responded to criticism by suggesting a double standard—that Democrats had crossed over to vote for John McCain, but were not criticized for doing so.

In order to switch parties in Ohio, voters are required to swear their allegiance—the penalty for doing so falsely can include fines and jail time. The Cuyahoga County, OH, Board of Election began investigating the crossover controversy on March 20, 2008, but there has been no official word on whether or not Limbaugh will be drawn into the investigation.

1. Twice the number of Republicans participated in the Ohio and Texas primaries, compared to other 2008 Democratic primaries
2. Hillary Clinton won both Ohio and Texas, furthering the battle for delegates between her and Barak Obama
3. 16,000 crossover votes in Cuyahoga County, OH, alone
4. Voter fraud is felony in OH
5. Penalty: 6-12 months jail time and $2,500 fine

1. This is too good a soap opera. We need Barack Obama bloodied up politically, and it's obvious that the Republicans are not going to do it and don't have the stomach for it. (The O'Reilly Factor, February 29, 2008)
2. So yes, I'm asking to cross over and, if they can stomach it — I know it's a difficult thing to do to vote for a Clinton — but it will sustain this soap opera, and it's something I think we need. It would be fun, too. (The O'Reilly Factor, February 29, 2008)
3. Look, half the country already hates Hillary. That's good. But nobody hates Obama yet. Hillary is going to be the one to have to bloody him up politically because our side isn't going to do it. Mark my words. It's about winning, folks! (The Rush Limbaugh Show, March 3, 2008)
4. I understand out there, many of you are worried here about my strategy. I don't even know if it's going to work... I'm not urging action. It sounds like I'm urging action, but you know I don't give marching orders here. I'm just thinking aloud and telling you what I think is important to happen here. (The Rush Limbaugh Show, March 3, 2008)
5. They are upset because they know it worked... It's not "mischief" when Democrats and independents choose our nominee, is it? No, no, no! That's democracy in action. (The Rush Limbaugh Show, March 5, 2008)
6. Can we talk about here the difference between legal and moral? Did I suggest people do anything illegal? And did people who cross over do anything illegal? And, therefore, is it immoral, what they did? (The Rush Limbaugh Show, March 5, 2008)
7. Think of us as "independent" conservatives, and what happened last night was that the mavericks and the independents among us voted for Hillary. If you think of us that way, maybe you will love us as much as you love our nominee. (The Rush Limbaugh Show, March 5, 2008)
8. These are Democrats, and they're fit to be tied. Look, they feel free to cross over all the time and have fun with our nomination process, as in Senator McCain in Iowa, New Hampshire, and so forth, and other states. They just don't like the same game being played by us. (The Rush Limbaugh Show, March 21, 2008)