WASHINGTON — Preaching to the converted on lower taxes and less regulation, Republican Mitt Romney courted more than 100 of America's top chief executives Wednesday demanding government be an ally of enterprise, "not the enemy."

The man challenging President Barack Obama for the White House in November made a rare visit to the US capital to hammer home his message that government must loosen the reins on corporate America and let business gallop ahead unburdened by excessive restrictions.

"Government has to be the partner, the friend, the ally, the supporter of enterprise -- not the enemy," Romney told a gathering of the Business Roundtable, a grouping of executives of leading US firms with some $6 trillion in annual revenue.

"Too often, you find yourself facing a government that looks at you like you're the bad guys," he said in a 20-minute speech before going into a closed-door discussion with his audience.

"I want to change the attitude (in Washington) and encourage the growth of enterprise in this country."

A key plank in the strategy would be reducing the regulatory burden on the US economy, which Romney said has tripled since Obama took office and now costs some $1.4 trillion per year, "even more onerous than the tax burden."

Romney has sought to cast Obama as unable to bring the sluggish US economy out of the worst recession in generations, and he pulled no punches at the roundtable, saying Obama has had "the most anti-investment, anti-business, anti-jobs series of policies in American history."

He also seized once more on the president's disastrous assurance last week that the private sector was "doing fine," saying the comment was met with "incredulity" by the public and suggesting Obama was out of touch with middle-class Americans.

Romney and Obama are fighting tooth and nail for the votes of the middle class in a pivotal group of swing states that could decide November's election.

But in Washington, Romney was addressing a constituency seen as firmly in his camp, and he used the opportunity to stress that implementing policies that help US businesses roar ahead is the number one way to create new jobs.

"I think this election is a watershed election which will determine the relationship between citizen and enterprise and government," Romney said.

He said his strategy involved luring back US companies that have sent jobs and manufacturing overseas by reducing the corporate tax rate from 35 percent -- which combined with state taxes is the highest rate in the world -- to 25 percent.

"Ultimately, over time, just like water flows to the lowest point, profits will flow to the place where taxes are lowest," he said.

Obama unveiled his own plan in February to cut the top corporate tax rate to 28 percent and choke off lucrative loopholes.