Candidates stand on stage during a Democratic presidential debate in Detroit on July 31. (Anthony Lanzilote/Bloomberg)
Opinion writer

On Thursday, 10 Democratic presidential candidates, including the five leading candidates, will be on the debate stage. This might be the last time for a while, given that Tom Steyer says he has now qualified for the October debate, which will necessitate two nights unless someone else drops out. (There is no better example of the Democratic National Committee’s negligence than allowing the debate stage to expand. The next round in November desperately needs a 3 percent polling threshold.)

As the candidates huddle with their teams to plan out their answers, they should keep in mind the following:

1. Debate boomlets fade very quickly. There is a far greater chance of hurting yourself with a stumble, an inanity or a moment of confusion than helping yourself with some exquisite zinger.

2. Democratic voters hate Democrats who attack other Democrats. Now is not the time for a frontal assault. Every invitation to quibble with another Democrat should be met with: “I’m not here to criticize fellow Democrats. But as for President Trump... ” If on the receiving end, the candidate should begin with, “I’m disappointed you are doing Trump’s work for him. But here is my actual plan... ”

3. Democrats love attacks on Sen. Mitch McConnell (R-Ky.). McConnell, who detests the nickname Moscow Mitch (for his failure to move on election security), has become the villain blocking progress on a host of popular measures. If candidates need a quick applause line — or evidence that compromise with Republicans might be impossible so long as Republicans have the majority — a quick reference to McConnell will come in handy.

4. Call out the embezzler in chief. Democrats want to see their eventual nominee skewer the president, so the contenders would be wise to audition for the role by taking on Trump over the right things. It’s essential, first and foremost, to start building the case that he is a kleptocrat out to make money for himself off the presidency. By routing money to his properties and receiving monies from foreign governments, he has become the most corrupt president in history. Democrats need to say so, not only to show off their rhetorical skill but also to begin chipping away at reluctant Trump voters and reminding independents that Crooked Donald makes Hillary Clinton look like a Girl Scout. Democrats should avoid “Lock him up!” chants, but “Pay it back!” might be very catchy.

5. Call out the craziness. Democratic voters know that Trump is “nuts” in common parlance, but candidates need to hammer home why that’s a big deal. (Only in the Trump era would such a statement be possible.) It puts people in danger (e.g. from hurricanes), leads to disgrace (inviting the Taliban to Camp David?!), destabilizes our economy, risks wars (against Iran and North Korea, before the love-fest) and makes it impossible to govern. He’s a menace to our economy and our national security.

6. Glue Trump to the fading economy. Job gains have been tapering off, the national debt is sky-high, manufacturing is declining thanks to his trade war and farmers are going bankrupt. Whatever window we had to spread the benefits of the economic expansion and extend it was blown on a tax cut that blew up the debt, benefited the wealthiest people and corporations. and didn’t deliver on sustained growth. Trump owns the results of his policies, and Democrats should make clear that the real risk is in staying with this president, not in dumping him.

7. If you’re a moderate, defend moderation. It’s not correct to say that moderates don’t have big, bold ideas. They have big, bold ideas that they know must come in bite-size pieces for the public to accept (e.g. a public option) without scaring people (e.g. outlawing private insurance, decriminalizing illegal border crossings). A big and bold idea has to be implemented for it to do any good.

8. If you’re a super-progressive, show you can be pragmatic. Sen. Elizabeth Warren (D-Mass.) has a ceiling on her campaign support unless she can reassure some moderates that she knows how to work with Republicans (She used to be one!), seeks to create an even playing field (i.e. functional markets), believes in the give-and-take of the legislative process and knows how to prioritize. Likewise, when opponents or moderators bring up the “socialism” label, she might remind voters that FDR saved capitalism with items such as Social Security, federal deposit insurance and the Tennessee Valley Authority.

Read more:

Jonathan Capehart: What to do and not do in the Democratic debates

Jennifer Rubin: The next debate offers two kinds of candidates

Amanda Ripley: How to redesign the debates for our current political climate

E.J. Dionne Jr.: Like it or not, electability matters

David Byler: The DNC had a smart plan for shrinking the Democratic field. What happened?

James Downie: Biden’s wall cracks as Warren and Sanders lay siege