AP Photo/Steven Senne Rep. Richard Neal, the incoming chairman of the House Ways and Means Committee, has indicated he wants to "lay out a case" first.

WASHINGTON ― The first thing Democratic lawmakers have to do to obtain copies of President Donald Trump’s personal and business tax returns is to send a letter to the Internal Revenue Service ― but they’re not going to do it this week.

And they might not even do it this month.

Rep. Richard Neal (D-Mass.), the incoming chairman of the House Ways and Means Committee ― who is legally entitled to see any American’s tax returns ― has indicated that he wants to wait and “lay out a case” so he doesn’t look too partisan.

Hesitating is a “big mistake,” said Steve Rosenthal, a senior fellow with the Tax Policy Center, a partnership of the Brookings Institution and the Urban Institute.

“Congress’ oversight responsibilities are clear and Trump’s tax returns are critical to that oversight,” Rosenthal said. “To pretend otherwise just plays into Trump’s narrative.”

“It is indefensible,” said Jeff Hauser, director of the Revolving Door Project at the liberal Center for Economic and Policy Research. “By being slow to act on this, Richard Neal is messing up both politically and legally.”

Politically, Neal is “acceding to the notion” that even beginning the process to obtain Trump’s tax returns is an “outrageous or drastic” act of a partisan nature, Hauser argued. Legally, he added, Neal’s hesitation just delays a likely effort by Trump and the Treasury Department to drag a tax return request through the courts.

Federal law says that in response to a written request from the Ways and Means chairman, the Treasury secretary “shall furnish such committee with any return or return information specified in such request.” A Treasury spokesperson told HuffPost last year that the department would review any such request to get the president’s returns “for legality,” strongly hinting that the Trump administration would not simply obey the law. This could mean a protracted legal battle.

“Trump may order the IRS to resist, but Neal should get the clock running,” Rosenthal said.

During the 2016 presidential campaign, Trump broke with decades of precedent by refusing to disclose his tax returns, which could reveal detailed information about his income, debts and charitable giving. Democrats previously said they would try to obtain the returns if they won back the House of Representatives in November, which they did. Democrats assume control of the House on Thursday afternoon.

Other Democrats on the Ways and Means Committee told HuffPost last month that they considered getting Trump’s tax returns a top priority. Rep. Bill Pascrell (D-N.J.) hinted that they were developing a strategy.

“We have thought about some things which I’m not going to communicate,” he said.

As for the prospect of a prolonged legal battle: “The law’s on our side,” said Pascrell. “There’s stronger reason now to do what we wanted to do than there was 18 months ago.”

Disclosures that Trump and his businesses may have fraudulently dodged taxes over the years make obtaining the president’s returns important as a policy matter, Rep. Lloyd Doggett (D-Texas) said.

“We need to look at whether we can have confidence that our tax laws are being fairly enforced,” Doggett said. “I see getting the tax returns as not an attempt to indicate partisanship against Trump but as part of the work we do in the administration of tax law.”