And get ready for some fireworks no matter what, as Donald Trump’s staying power at the top of the polls will force everyone on stage to go after the leader. Carly Fiorina is best positioned for it. She’s risen enough in polling of late to get to the main stage, and her “Faces” ad today got rave reviews. She seems to be peaking at the right moment to spark a head-on argument on Wednesday:

Donald J. Trump has criticized Carly Fiorina’s looks, saying of his only female Republican rival: “Look at that face! Would anybody vote for that?” He has said that listening to Mrs. Fiorina’s voice gives him a “massive headache.” He has mocked her business career, and has gleefully declared how “viciously” she was fired by Hewlett-Packard.

On Wednesday, Mr. Trump will share a stage with Mrs. Fiorina for the first time, in the second Republican presidential debate.

Political strategists warn male candidates to use caution when debating against a female rival. But almost never before in American presidential politics has a candidate who has drawn charges of sexism and bullying been forced to personally confront the female recipient of his insults on live television. And with Mrs. Fiorina bragging that she is getting under Mr. Trump’s skin, their showdown is emerging as one of the most intriguing subplots of the second debate.

In the first Republican debate last month, Mr. Trump defended having called women “fat pigs” and “disgusting animals,” and he later implied that the moderator, Megyn Kelly of Fox News, had asked him tough questions because she was menstruating, a comment that got him disinvited from an influential conservative gathering where Mrs. Fiorina gave a rousing speech.

Amy Chozick and Patrick Healy note that Trump has been telling people that he can’t wait to attack Fiorina over her dismissal from Hewlett-Packard. Bloomberg’s Josh Rogin may provide more fodder for Trump’s attack:

On the campaign trail this year, Carly Fiorina has been a staunch advocate of keeping crippling sanctions on Iran, but under her leadership, Hewlett-Packard sold hundreds of millions of dollars’ worth of products to Iran through a foreign subsidiary, despite strict U.S. export sanctions.

Fiorina, who served as CEO of Hewlett-Packard from 1999 to 2005, often criticizes President Obama’s deal with Iran on the basis that he is agreeing to sanctions relief for Iran too quickly and in exchange for paltry concessions on the part of Tehran. In April, she said Iran sanctions were “unraveling fast,” something she called a “dangerous development.”

Fiorina often cites her time as a corporate executive as a credential for running for president and said in July she would back away from the Iran deal if elected and renegotiate. She has also warned that European countries, as well as Russia and China, are rushing “to open the Iranian economy.” She has also accused Iran of cheating on sanctions.

What Fiorina never mentions on the stump is that while she was in charge, Hewlett-Packard used a European subsidiary and a Middle East distributor to sell hundreds of millions of dollars of printers and other computer equipment to Iran.

As Rogin notes, this came up during Fiorina’s 2010 Senate campaign against Barbara Boxer, too. At the time, she argued that HP’s business did not violate the sanctions laws, and most of it came from the sales of printer ink. She also argued — somewhat contradictory to her position now — that this kind of trade could open Iran to a more moderate regime and force the mullahs to account for their brutality:

“HP, in full compliance with American export laws, was distributing printer ink. Dell sells PCs, Apple sells iPhones, and certain printer ink was permitted in export law.” “But isn’t it wonderful that Dell PCs and Apple iPhones are in Iran, because this is why we know that a woman has been condemned to be stoned to death because she is accused of adultery. This is how we know that this regime kills demonstrators and tortures political activists. The knowledge that we gain about was going on there is important. It gives us a human face on a brutal regime.

Fiorina may have to answer questions about that from Jake Tapper or the other panelists at the CNN debate (full disclosure: Salem Media Group is a partner in the debate), if not from Trump. Trump will likely focus more on Fiorina’s executive abilities, but an attack on this could sting, especially with the Republican focus on the Iran nuclear deal. Most of the candidates will reliably declare that they would scotch the deal on Day One, and other candidates than Trump may use that opportunity to take some wind out of Fiorina’s sails.

The first debate turned out to be surprisingly substantive and competitive. A Fiorina-Trump battle might elevate this debate, too, especially given Fiorina’s solid preparations all throughout this cycle. Trump may hit Fiorina on Iran, but Fiorina may have a couple of surprises for Trump on his executive track record, too.