Congress and investigators are circling around President Donald Trump’s children. Will the coming battle be the most personal yet?

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The Trump business, brand and identity have always been a family affair. The Trump Organization began in 1923 as E. Trump & Son — because Elizabeth Christ Trump had to sign the checks for her son, the precocious Fred Trump, who had not yet turned 21 when he started building in New York.

Fred’s son Donald Trump took over the family business in 1971 and made it a global symbol of Manhattan luxury while cultivating the personal brand that would make him president of the United States 45 years later. He then proceeded to install his two oldest sons, Don Jr. and Eric, atop the business, and daughter Ivanka in the White House — along with her husband, Jared Kushner, himself a real estate scion of considerable means.

This mixing of blood, business and politics has led to some of the stickiest scandals of a presidency full of them. Now the question for prosecutors and Congress is how far to push the familial bonds.

We learned this past week that Trump himself pushed to procure security clearances for Ivanka and Jared, over the objections of White House staff, raising questions about what red flags in their backgrounds prompted those concerns. Last year, the Chinese government approved several trademarks for Ivanka’s business as the Trump administration continues to conduct high-stakes trade negotiations with Beijing, another example of a potential mixing of Trump family profits and official U.S. business.

As if being Donald Trump’s daughter isn’t the hardest job in the world. Ivanka Trump

Don Jr. holds the most perilous position of the progeny. He helped set up the infamous Trump Tower meeting with a Russian lawyer promising dirt on Hillary Clinton. And when The New York Times first reported the meeting, Donald Trump dictated a misleading statement in Don Jr.’s name about the meeting. Don Jr. also could be in hot water for lying to Congress about the Russian lawyer meeting or negotiations around building a Trump Tower in Moscow — the same offense for which attorney Michael Cohen is soon going to prison.

One of the many great Robert Mueller mysteries is if and when he will indict Don Jr., but it appears the special counsel knows what a political bombshell it would be. If it happened, it likely would be the final act of his investigation. And it’s hard to say how effective it would be. Who could blame a dad for wanting to pardon his son?

The multiple lines of inquiry for House Democrats — who this week issued document requests from 81 Trump-tied people and entities, including Don Jr., Eric Trump and Kushner — go far beyond Mueller’s purview. But the idea of going after the kids is no less difficult for them.

“The optics don’t work for us, in my opinion,” Rep. Gerry Connolly, a Virginia Democrat, told The Washington Post this week in a story about Democratic hand-wringing over what to do about the younger Trumps. “It easily plays into the victimhood narrative on the Republicans’ side.”

Don’t expect that to stop them, as the cries of “witch hunt” from across the aisle will not cease, no matter what Democrats do. Now there are plenty of ways for Democrats to overreach as they probe every crevice of Trump’s life, and political sensitivities might mean the kids get kid gloves. But the legitimate questions around the president’s administration, campaign, inauguration and business inevitably involve his family — because that’s been the Trump way for nearly a century.

“The press seems to think it is ironic that I, born of great privilege, think people want to work for what they are given,” Ivanka Trump told a room full of reporters and political bigwigs as part of a comedy routine at last weekend’s Gridiron Dinner in Washington. “As if being Donald Trump’s daughter isn’t the hardest job in the world.”

It’s about to get harder.

Read more: The Mueller Thread — how Ken Starr’s leaks could help Trump.