The Trump campaign is due to deliver a major speech today at historic Gettysburg, Pennsylvania. He will present his closing arguments for American voters, outlining the steps he will take in his first 100 days to make America great again. I hope it’s his best speech yet.

For all his gaffes and misstatements, the fact is that the race is not over until it’s over. (Even when he means it’s over.) So, as Mr. Trump heads into his Gettysburg address, I want to emphasize what he should replay from last week’s debate, and what he needs to emphasize more.

I’ll begin with where Mr. Trump shined in Las Vegas: His support of a ban on late-term partial-birth abortion was a heaven-sent gift from God. Mr. Trump’s opposition to abortion, in general, is a wonderful thing. So is his pledge to nominate pro-life judges, and his related idea that if pro-life judges overturn Roe v. Wade, that’s fine. Send abortion back to the states where it started.

So I sincerely hope that in Gettysburg, just as President Lincoln defended the ending of slavery, Mr. Trump continues to defend the life of the unborn. And I hope he contrasts his position with that of Hillary Clinton, who would permit abortions even in the ninth month — an un-American, anti-ethical stance that is meant to curry favor with left-wing women’s groups.

Next, on the economy, which is the number-one issue this campaign, Trump has some expanding to do. In last week’s debate, he briefly set forth his business tax cuts. But in the face of Secretary Clinton’s left-wing, “trickle down” critique of tax cuts for investors and the rich, he didn’t make the sale.

Instead, he veered off the tax-cut course, launching a tirade against Germany, Japan, South Korea, NATO, and Saudi Arabia for not paying enough to shoulder the American defense umbrella. He let Hillary off the hook.

He did commendably suggest that America could grow at 4%, 5%, or even 6%, and that growth is the ultimate solution to reducing our deficit and debt burden. And he did restate his pledge to repeal and replace Obamacare. But only relentlessly hammering on the details of the economic rejuvenation of America can win this thing, if only he’ll get down to it.

So for Gettysburg and beyond here are a few simple points that Mr. Trump should make — over and over and over again:

Reduced marginal tax rates on individuals and business fosters growth every time. So why not point to the tax-cut successes of Democrat John F. Kennedy and Republican Ronald Reagan? They reached across the aisle to create nonpartisan tax-cut coalitions that succeeded in launching booms of 4 to 5 percent.

And why not remind voters that President Clinton, after raising income taxes in his first term, which resulted in slower growth, aligned himself with Republicans to slash the capital-gains tax by 30%, resulting in a late-90s economic boom?

Without rancor and with civility, these presidents rejuvenated American prosperity. That’s the art of the deal.

Mr. Trump should also attack Mrs. Clinton’s class-warfare tactics. Research overwhelmingly shows that the biggest gainers from steep business-tax reduction — such as 15%, down from 40% for large and small businesses — are middle-income wage earners.

Yes, in a highly progressive tax code, successful top-end earners benefit in dollar terms from across-the-board tax cuts. But Mr. Trump would slash middle-income tax brackets to 12%, 25%, and 33%. And he would double the standard deduction, slash the marriage penalty, and provide child health-care assistance. These are winners for the middle class.

Sell it, Mr. Trump.

Like this: “My tax cuts will put more money in your pocket. Hillary’s trillion-dollar tax hikes will take money out. My plan will repatriate nearly $3 trillion in overseas cash for investment, jobs, and wages. America will become the best destination for global capital, and this investment will restore productivity to raise our standard of living.”

He might also say: “It defies common sense that Secretary Clinton’s trillion-plus-dollar tax hike will boost the economy, and that her multi-trillion-dollar spending will succeed where President Obama’s failed. She keeps talking tax hikes. Well, there she goes again.”

He also might add: “Like JFK, Reagan, and Bill Clinton, we will once again have a strong and reliable King Dollar.”

And in summation he can say: “I have a prosperity plan. My opponent has a recession plan.”

In other words: Please be blunt, Mr. Trump. The economy is the key issue. Hillary Clinton’s formula will not work.Working in a bipartisan manner, with Congress and the support of the American people, Mr. Trump can in fact make America great again.