Daddy's little girl on the hot seat

When two Republican members of Congress began formally questioning last week Ivanka Trump’s use of private email for government business, it was seen by people close to the White House as a sign of things to come for the president’s family.

One of the Republicans was Senator Ron Johnson of Wisconsin, the chairman of the Senate Homeland Security and Governmental Affairs Committee, which has conducted little oversight of the Trump White House until now.

The other was Representative Trey Gowdy of South Carolina, the chairman of the House Oversight Committee, who previously led a two-year investigation into events surrounding the attack on American diplomatic outposts in Benghazi, Libya, focusing relentlessly on the role of Hillary Clinton. His most prominent investigation as chairman has scrutinized alleged anti-Trump political bias within the F.B.I. during its inquiries related to the 2016 presidential campaign.

“That you now have Republicans investigating members of the first family is an indication of the perils ahead” for the Trumps, said Tom Davis, the former House Republican from Virginia who was the chairman of the Oversight Committee from 2003 through 2006.

Mr. Gowdy, who is retiring from Congress in January, will have little to do with any investigation, and his role in endorsing the inquiry was seen as pro forma. In his place as chairman of the committee will be Representative Elijah E. Cummings of Maryland, one of the newly empowered House Democrats eager to take on the Trump administration.

The Democrats are already laying out lines of inquiry that could quickly lead not just to Mr. Trump and his White House aides, but also to his immediate family. And Republicans returning to Capitol Hill next year may be forced by the changed political climate to take a harder line toward the Trump family.

Likely Democratic targets include not only the president’s personal finances and those of the Trump Organization, but also the actions taken by his sons Donald Jr. and Eric and his son-in-law, Jared Kushner, during the 2016 campaign and its aftermath.

The Oversight and Judiciary Committees are likely to focus on any violations of the Constitution’s emoluments clause, which bans payments from foreign governments to federal officeholders, an avenue that will lead to an examination of payments to Trump-held properties and the role of both of his sons and Mr. Kushner. And some investigators may try to question Donald Trump Jr. again about a meeting he held with a Kremlin-linked lawyer promising “dirt” about Mrs. Clinton.

While some of the areas primed for inquiry — most notably, ties between the Trump campaign, the Trump Organization and Russia, and possible campaign finance violations — are likely to overlap with investigations by the special counsel, Robert S. Mueller III, and federal prosecutors in New York, Democrats believe they have a broader mandate to question everything from foreign business dealings by Ms. Trump and the Trump Organization to the administration of security clearances at the White House, including the one given to Mr. Kushner.

Mr. Trump has told aides that he believes that Democrats have the potential to appear overly partisan in investigating his family and that voters may be sympathetic to efforts to rebuff them.

Thomas M. Reynolds, a former congressman who was the chairman of the National Republican Congressional Committee in 2006, agreed that the incoming House majority would be wise not to meddle excessively in the private affairs of the president’s business and two adult sons.

But, he said, “we’re on a thin line here because the president still owns the company.”

Both Mr. Kushner and Ms. Trump were advised by White House lawyers of the risks of joining the West Wing as formal advisers two years ago, since it would open them up to official lines of inquiry, among other issues. On the other hand, people close to them noted that they might be shielded by executive privilege in some instances, whereas the president’s adult sons, who do not serve in the administration, are not.

Democrats have said they will not reflexively file subpoenas, but they have already gotten signals from the White House that cooperation is likely to be minimal. Even if the Mueller investigation ends in the coming months, as Mr. Trump’s lawyers believe is possible, the White House is facing a string of congressional subpoenas that could grind the gears of government to a halt, and put a spotlight on areas that the secretive Mr. Trump prefers to keep out of sight.