• Donald Trump unveiled several new manufacturing proposals at a rally in Savannah, Georgia, in an effort to sharpen his economic platform as Vice President Kamala Harris prepares a new policy rollout of her own.
• Trump said he would give U.S.-based manufacturers a first-year tax write-off for all R&D expenses, walking back a major component of his 2017 tax law.
• The former president also said he would appoint a specialized "manufacturing ambassador" if he wins a second term in the White House.

Former President Donald Trump unveiled several new manufacturing proposals at a rally in Savannah, Georgia, on Tuesday, part of an effort to sharpen his economic platform as Vice President Kamala Harris prepares a new policy rollout of her own.

The Republican presidential nominee said if he were elected, he would reward U.S.-based manufacturers with expanded research and development tax credits, which would allow businesses to "write off 100% of the cost of heavy machinery and other equipment in the first year."

If implemented, this proposal would reverse a major component of Trump's 2017 Tax Cuts and Jobs Act, which phased out traditional R&D tax credits.

Starting in 2022, businesses were no longer allowed to write off their R&D expenses the same year they incurred them. Instead, they have to amortize their R&D costs over five years and then write off that value, the effect of which is often to shrink the tax benefits.

Trump's proposal on Tuesday appeared to walk back that piece of the TCJA. "You're going to get full expensing. In other words, you have a one-year write-off," he said.

The former president also said he would appoint a specialized "manufacturing ambassador" if he wins a second term in the White House. This appointee would be solely responsible for traveling around the world to "convince major manufacturers to pack up and move back to America," Trump said.

Trump also doubled down on his hardline approach to trade, saying he would impose a "100% or 200% tariff" on cars imported from Mexico.

With 42 days until the Nov. 5 election, Trump is working to strengthen his economic posture, as Harris beefs up her own platform and works to cast her Republican opponent in a negative light.

Earlier Tuesday, the Harris campaign hosted billionaire investor Mark Cuban and Teamsters National Black Caucus Chair James Curbeam on a campaign call, where they panned Trump's economic agenda.

"The Vice President, her team thinks through her policies," Cuban said. "She doesn't just off the top of her head say what she thinks the crowd wants to hear, like the Republican nominee."

Harris has received some criticism of her own from economists and the business community, especially pertaining to her aggressive approach to regulating corporations.

Cuban on Tuesday worked to assuage some of corporate America's concerns.

He argued, for example, that Harris' proposed corporate tax hikes would put less pressure on companies than Trump's across-the-board tariffs would. He also said he does not believe a Harris administration would impose heavy regulations on cryptocurrencies.

"I think she's better for business," said Cuban.

On Wednesday, Harris is expected to roll out new economic policy proposals in a speech in Pittsburgh.