A top Senate Democrat said just because other presidents have created "czars" to carry out administration policy does not mean President Obama is right to follow their lead - and warned that Congress may have to step in and keep White House appointees in check.
Senators say the arrangement goes against the Constitution because many czars are never vetted by Congress, even though they have a major role in making policy.
But there may be few options for reeling them in. Experts told Sen. Russ Feingold, the Wisconsin Democrat who convened a hearing on the issue, that the tools available are either to cut off funding for the positions or write laws to control how much authority Congress gives the president.
"While there is a long history of the use of White House advisers and czars, that does not mean we can assume they are constitutionally appropriate," said Mr. Feingold, chairman of the Judiciary Committee's Constitution subcommittee.
Controversy has swelled in recent weeks as conservative commentators such as Fox News' Glenn Beck and Republican lawmakers have challenged the practice. The White House and its Democratic allies have hit back, arguing that many of the positions existed under previous administrations.
The number of czars in the Obama administration varies depending on the definition of the term, with one Republican senator counting 18 and Mr. Beck citing 32.
The White House declined to provide a witness for Mr. Feingold's hearing, which press secretary Robert Gibbs mocked Tuesday.
"I don't know if Sen. Feingold's calling Franklin Roosevelt to be a witness," Mr. Gibbs said. "I would assume that Congress and Sen. Feingold have more weighty topics to grapple with than something like this."
But Mr. Feingold isn't the only Democrat to express concern on the topic. Sen. Robert C. Byrd of West Virginia, the longest-serving lawmaker in Congress, has also criticized the administration for impinging on congressional authority, as has Sen. Joe Lieberman, a Connecticut independent who caucuses with the Democrats.
Lawmakers made clear Tuesday that not all czars are created equal. For example, "intelligence czar" Dennis Blair is actually the director of National Intelligence, a position created by Congress following a recommendation by the 9/11 Commission. By his count, Mr. Feingold said there are as many as 10 czars who could be exercising authority that has not been delegated to them by Congress.
The Appointments Clause of the Constitution gives the president the authority to make appointments with the advice and consent of the Senate but says that, "Congress may by law vest the appointment of such inferior officers, as they think proper, in the president alone."
Constitutional experts advised senators that it is within their power to ask unconfirmed czars to testify before Congress, though they are not bound to do so. One expert suggested that overly broad legislation, such as the financial bailout bill, cedes too much authority to the executive branch for implementation.
"Congress needs to be more careful in the types of legislative discretion it gives, which in many cases gave rise to the creation of these czars in the first place," said Matthew Spalding, director of the B. Kenneth Simon Center for American Studies at the Heritage Foundation.