The book is called Clinton Cash: The Untold Story of How and Why Foreign Governments and Businesses Helped Make Bill and Hillary Rich—and it could be the undoing of a woman much of the country assumed would one day hold the presidency.

Peter Schweizer’s latest work won’t officially hit stores until May 5, but the buzz generated by the release of advance copies already has Team Clinton on defense, and Republican heavy-hitters running offense against the financial history of the Clinton Foundation.

The basic premise of the book is that during the time Clinton served as secretary of state, the Department would grant favors to foreign entities in exchange for high-dollar speaking fees paid directly to the Clinton Foundation.

“We will see a pattern of financial transactions involving the Clintons that occurred contemporaneous with favorable U.S. policy decisions benefiting those providing the funds,” Mr. Schweizer writes.

His examples include a free-trade agreement in Colombia that benefited a major foundation donor’s natural resource investments in the South American nation, development projects in the aftermath of the Haitian earthquake in 2010, and more than $1 million in payments to Mr. Clinton by a Canadian bank and major shareholder in the Keystone XL oil pipeline around the time the project was being debated in the State Department.

The Clinton Foundation has come under scrutiny for accepting foreign donations while Mrs. Clinton served as secretary of state. Last week, the foundation revised its policy to allow donations from countries like Germany, Canada, the Netherlands and Britain but prohibit giving by other nations in the Middle East.

Kentucky Senator and presidential contender Rand Paul has been beating this drum since early this month:

Paul had debuted this theory on April 7, in the interview he gave Fox News’s Sean Hannity right after his announcement. “She’s in charge of approving business deals as secretary of state,” Paul said of Clinton. “They’re called CFIAs, anything that relates to our security. There’s going to be something coming out in the next few weeks about companies that she approved deals for.”

“That they were against, and then they became for after money went to the foundation?” asked Hannity.

“Significant amounts, over $100 million being given to her foundation coming out in the next two weeks,” said Paul.

The next day, in New Hampshire, Fox News’s Carl Cameron asked him what the scandals might be.

“I think there is big news coming on the Clinton Foundation,” said Paul. “I think there are things that went on at the Clinton Foundation that are going to shock people. I think they’re going to make people question whether she ought to run for president.”

Late last week, he teased the scandal again during a speech at an SBA List event, saying that “[t]here’s going to be stuff coming out about the Clinton Foundation and their donations,” and alluding to collusion between the State Department and foreign corporations.

If conservatives are to launch an effective PR campaign against Hillary Clinton, this is the way to do it—one brick at a time. Persistence is key here; her team has handled situations like this before. They (at least to some extent) know what they’re doing, and they know that they can beat the heat if they’re just one cycle more persistent than the most persistent Republican.

Could this be the issue that leads to Clinton’s undoing? I haven’t read the book yet, so I couldn’t tell you. All I know is that this type of issue is the stuff that oppo researchers dream about at night.

I’m happy to assume it’s at least something. We can work with that.

You can listen to Senator Paul’s speech to SBA List here (h/t Bloomberg):