Some Republican lawmakers have expressed concern at President Donald Trump's frequent resort to calling for investigations on a variety of issues.
The latest example of this was Trump's call for an inquiry into whether former President Barack Obama wiretapped his phone during the election campaign, Politico reported.
Republican senators and congressmen have warned that investigations could provide Democrats with a platform to attack the White House and make public other allegations.
"He's opened that door," independent Sen. Angus King of Virginia told Politico.
Trump has called for several investigations since coming to power, including one into his allegation that between 3 and 5 million people voted illegally in the November 2016 election. He suggested this after being asked why he had lost the popular vote to Hillary Clinton.
"I don't see any evidence of that. We're not doing an investigation of that," Republican Rep. Jason Chaffetz of Utah, House Oversight Committee chairman, said of the proposed inquiry into illegal voting.
Those who knew Trump in his business days say his frequent calls for investigations are not new.
"His first move was to threaten to sue you," an anonymous lobbyist who dealt with Trump told Politico. "He loved to sue people. He loved throwing lawsuits around."
But Trump's approach also has some supporters. Sam Nunberg, a former Trump aide, explained that the latest allegation against Obama had served its purpose.
"The tweets keep his base motivated," Nunberg added. "I would not have attacked the president directly, however President Trump's tweets completely changed the narrative and got Clapper to admit there was no connection between the Russian government and the Trump campaign."
Nunberg was referring to a comment made by former Director of National Intelligence, retired Lt. Gen. James Clapper, who said that there was no evidence to suggest collusion between the Trump campaign and Russia.
There has also been no evidence presented to suggest that Trump was the target of an investigation during the election campaign.
"There is no reason that we have to think the president is the target of any investigation whatsoever," White House press secretary Sean Spicer said March 8, according to the New York Times.
Not all of Trump's appeals for investigations have been quite as serious. On March 3, Trump tweeted "We should start an immediate investigation" alongside a 2003 picture showing Democratic Sen. Chuck Schumer of New York eating doughnuts with Russian President Vladimir Putin at a New York gas station.
Republican Rep. Devin Nunes of California, chair of the House Intelligence Committee, suggested that the media was partly responsible.
"I think a lot of the things he says, you guys sometimes take literally," Nunes said, Politico reported. "Sometimes he doesn't have 27 lawyers and staff looking at what he does, which I think is at times refreshing."