Wednesday’s debate at the Ronald Reagan Presidential Library may be the most important debate of the 2023 Republican presidential nomination process. 

It is to the candidates’ advantage that President Trump will be in Michigan addressing auto industry employees amid the United Auto Workers strike. His absence will create a space in which they can talk about the solutions America needs. If Mr. Trump were there, everyone else would be overshadowed — and all news coverage would obsess over him and various reactions to him.

As we saw in the first debate, when given a chance to talk about issues and ideas, the candidates are competent and interesting. They have strong personalities, and they offer viewpoints and ideas worthy of national attention.

This week’s debate is important because it may determine if anyone can break past Governor DeSantis and become a true competitor to Mr. Trump.

But becoming a real contender is still a huge challenge. Consider the Real Clear Politics average of the most recent polls:

Mr. Trump leads with some 57 percent of Republicans backing him. Mr. DeSantis stands at 14.5 percent. The former UN ambassador, Nikki Haley, has the backing of 5.6 percent of Republicans, and entrepreneur Vivek Ramaswamy stands at 5.1 percent. 

The rest of the field is pulling less than 5 percent:
• Vice President Pence (4.3 percent)
• Senator Scott (2.8 percent)
• Governor Christie (2.8 percent)
• Governor Burgum (1 percent)
• Governor Hutchinson (0.6 percent).
Note, Mr. Hutchinson will not debate on Wednesday, because he did not meet the polling threshold. 

Mr. DeSantis started the year as the dominant alternative to Mr. Trump. For a variety of reasons, he has since faded. In fact, Mr. DeSantis is now almost 43 points behind Mr. Trump. Given all the press coverage early in Mr. DeSantis’ candidacy — and the substantial amount of money he raised — his slide has been the biggest Republican story this year. 

Major donors who started the year investing their hopes and money in the Florida governor have become disappointed and disillusioned. They have broken into three groups.

Some are drifting toward the No Labels effort to create a third party of moderate problem solvers. Others have given up and decided to support Mr. Trump (or shifted focus to Senate and House races). The third group is actively looking for a new challenger.

It’s the third group on which the debaters this Wednesday must focus. If someone hits a home run with language, ideas, and/or attitude, a substantial number of disheartened and despairing anti-Trump donors may notice — and decide to write really big checks.

Overall debate performance is not all that matters. In this kind of wide-open environment — with seven candidates maneuvering to become the Trump alternative — candidates have two simple goals. 

First, do not get too eager and screw up. One big mistake could lead people to write you off as unable to beat Mr. Trump or lead the country. 

Second, find no more than three breakthrough moments in which your ideas, language, delivery, intelligence, courage, and authenticity vividly come through. Networks will specifically hunt for these moments to highlight repeatedly. And they will go viral on social media. 

Ambassador (and former Governor) Haley came close to breaking through after the first debate. Many polls showed that people felt she was the most effective and forceful debater. Her focus on Vice President Harris worked to her advantage. 

Ms. Haley’s range of experience in foreign policy and national security was impressive. Her toughness about balancing the budget and lessons she learned as a reform governor of South Carolina communicated an important authenticity. She may be the best positioned to break out.

Mr. Ramaswamy impressed in the first debate. As a remarkably successful 38-year-old entrepreneur, he has a lot going for him. However, many people refuse to consider him because they don’t believe he has enough experience to be President. If he can perform well enough to overcome those concerns, he could take off and have an exciting run.

Mr. DeSantis may be facing his last chance to prove he is a contender. He has been an excellent governor of Florida. It has been perplexing to watch him decay under the dual assaults of the Trump team and the left-wing press. This may be his last opportunity to resurrect his candidacy and convince people — especially major donors — to give him a second look.

It will be an interesting and important debate. It is worth your time to watch and think about it.