Milwaukee (AFP) - As criminal charges against Donald Trump mount, his rival for the White House President Joe Biden is determined to avoid commenting on the Republican's legal troubles. 

A day after Trump was indicted for the fourth time, for alleged racketeering and election interference in Georgia, Biden delivered a public speech in another key swing state, Wisconsin, focused on wind power and job creation.

In a factory busy with new orders for wind turbines, the Democrat boasted of new jobs and investments linked, in his view, to the major energy and infrastructure policies he has enacted during his first term.

Though the speech was aimed squarely at countering Trump's message of American decline, he was careful not to even mention his predecessor's name -- and certainly not the Georgia indictment.

"They tell us America is failing," Biden said of Republicans' political messaging.

"They are wrong... America isn't failing. It's winning."

Asked about Trump's latest legal development, White House spokeswoman Olivia Dalton said Tuesday aboard Air Force One that she was "certainly not going to comment."

Biden is walking a careful line ahead of his possible 2024 rematch with Trump, who remains the frontrunner for the Republican nomination.

Trump's refusal to accept his 2020 election loss to Biden has led to the slew of indictments against him -- first in federal court in August, and again in the southern state of Georgia on Monday, where he was painted as leading a Mafia-like operation to subvert Biden's victory.

Biden, 80, has maintained his silence since Trump was hit with his first indictment -- in New York earlier this year, over hush-money payments made to porn star Stormy Daniels.

The US leader knows that the slightest comment he makes will be seized on by rival Republicans as alleged proof that he has unleashed the Justice Department to immobilize his likely 2024 opponent.

Already not fond of speaking with reporters, Biden has carefully avoided the press since the beginning of the summer and their persistent questions about Trump.

He frequently ignores shouted questions as he boards his plane or while taking bike rides at his beachside home in Delaware.

The Democrat instead sticks to well-practiced speeches on major economic policies, especially his signature "Inflation Reduction Act."

While its name was designed to show Americans he was taking action over rising prices, the gut of the policy is incentives for investment and job creation in the renewable energy sector.

Biden says it has already generated $110 billion in private investment.

"In Wisconsin alone, companies have committed over $3 billion in manufacturing and clean energy investments since President Biden was sworn into office," the White House said Tuesday.

'Sense of honor'

For his 2024 reelection campaign, Biden likely knows he cannot drown out all the noise about Trump's indictments and coming trials.

But he is betting that ultimately the robustness of the US economy, which has defied predictions of recession, will convince voters to support him. 

To set himself out from his rival, Biden does not see the need to stoke the fires of Trump's legal woes.

Equally so, he is mute on the legal problems of his own son, Hunter Biden, who faces possible criminal tax and other charges from a Justice Department special counsel appointed just last week.

While that drew big headlines, it was quickly eclipsed by Georgia's indictment of Trump.

Still, Biden faces an uphill battle. 

Opinion polls show he has a low confidence rating among voters, who don't completely understand his economic policy and are put off by his age. If reelected, Biden would be 86 when he finishes his second term.

Still, at the peak of a five-decade political career, the US leader is gambling that time favors him and that voters will prefer his personality to Trump's.

"This is still a country that believes in honesty, decency and integrity," Biden said Tuesday in a thinly veiled swipe at his Republican opponent.