(Recasts; adds presidential tweet, fresh quotes and details)
WASHINGTON, Aug 1 (Reuters) - U.S. President Donald Trump sent a Twitter message bragging about corporate America's high profits under his presidency on Tuesday, prompting critics to say he was undercutting Republican arguments in favor of a tax cut for corporations.
As Republicans in Washington try to refocus on taxes after the collapse of their failed drive to repeal Obamacare, Trump sent a morning tweet that said: "Corporations have NEVER made as much money as they are making now."
Corporate lobbyists and Republicans consistently argue that a cut in the corporate income tax is needed to help corporations be more competitive. But highlighting corporate profits could diminish that argument.
"This is a weird way to launch their proposal to cut corporate taxes," said Democratic Senator Brian Schatz of Hawaii, in a tweet of his own responding to Trump.
More than six months into his presidency, Trump still sends out tweets that catch aides and allies off guard and sometimes clash with Republicans' messaging on their policy agenda.
The latest tweet seemed to fly in the face of Republican rhetoric that supports cutting the current 35-percent corporate income tax rate, one of the world's highest on paper.
The Trump tweet "takes the edge of urgency off the plea to reduce the burden on corporations," said William Galston, a senior fellow at the Brookings Institution think tank.
"There's not an obvious harmony between those two conversations," Galston said.
Congress is working on tax legislation and targeting a House of Representatives vote in October and Senate vote in November. Trump is expected to travel the country to make the tax reform case. But there is little consensus on the issue, and analysts said an October-November target could be too ambitious.
The White House insists on cutting the corporate rate to 15 percent, while House Republicans favor 20 percent. A top Senate Republican this week said lawmakers would be lucky to get it down to 25 percent.
On Tuesday, Senate Democrats offered to work with Republicans on a bipartisan tax package, but only if it does not cut taxes for the wealthy, add to the federal deficit or allow Republicans to enact legislation on their own.
In a letter to Trump and Senate Republican leaders, 45 lawmakers led by Senate Democratic leader Chuck Schumer said a bipartisan effort would raise wages for workers, grow jobs, promote investment and modernize the business tax system. (Reporting by David Morgan; Editing by Cynthia Osterman and Kevin Drawbaugh)