Elon Musk's government reform plan adopted by Trump, economic blueprint unveiled before Harris debate.

• At the Economic Club of New York, former President Donald Trump will reveal a fresh batch of economic policy proposals.
• Trump is preparing to refine his policy argument five days before he goes up against Harris in an ABC News debate on Sept. 10.

Former President Donald Trump on Thursday presented a set of economic policy proposals that incorporate CEO Elon Musk's suggestion of establishing a government efficiency commission to reduce wasteful federal spending, targeting the Biden-Harris administration's spending levels.

In a speech to the Economic Club of New York, Trump announced that the commission he appointed will create an action plan to completely eradicate fraud and inappropriate payments within six months.

The billionaire entrepreneur has repeatedly expressed his willingness to lead a commission without pay, title, or recognition.

Trump's endorsement of Musk's plan marks a significant shift in their relationship, moving away from their bitter rivalry to a more amicable alliance, as they were engaged in a public spat two years ago, trading barbs with each other.

The government efficiency commission presents Trump with a concrete proposal to attach to his criticisms of what he views as unnecessary spending in the Biden-Harris administration.

"Trump stated in his Thursday speech that it's time for Comrade Kamala Harris to return to California. He argued that she seeks four more years to implement a radical left agenda that poses a significant threat to the prosperity of every American family and America as a whole. Trump emphasized that this is about America itself."

In his speech, Trump reiterated his plans to reduce the corporate tax rate to 15% and eliminate specific provisions of President Biden's Inflation Reduction Act.

Trump stated, "I am giving my promise for low taxes, fewer regulations, and reduced energy expenses."

Trump praised his own achievements during his first term, such as implementing a strict tariff policy on China and reducing the corporate tax rate from 35% to 21%.

Trump stated, "I managed our economy the same way I would manage my own business."

Trump's economic plans have faced opposition from economists and Wall Street analysts due to their high cost, including his proposal to impose tariffs on all imports.

Trump delivers a speech on Thursday as he fine-tunes his policy message four days before he debates Harris on ABC News on Sept. 10.

— CNBC's Josephine Rozzelle contributed to this report.

This is a developing story. Check back for updates.