Numerous unprecedented conflicts of interest that Donald Trump will bring with him to the White House were set forth by the New York Times over the long holiday weekend. The billionaire developer has significant business dealings in at least 20 countries, many of them major geopolitical actors that impact core American interests. “Several of Mr. Trump’s real estate ventures in India—where he has more projects underway than in any location outside North America—are being built through companies with family ties to India’s most important political party,” the newspaper reported. In that country, as in China, Turkey, Saudi Arabia, Indonesia, Brazil, Argentina, and beyond, there will be countless occasions where the interests of the United States and the Trump Organization diverge.

Will President Trump ever put his business interests or the entrepreneurial efforts of his children, who plan to run his company, ahead of the American public’s interests? Journalistic organizations will try to play watchdog to guard against the possibility.

But as the New York Times itself acknowledges, “the true extent of Mr. Trump’s global financial entanglements is unclear, since he has refused to release his tax returns and has not made public a list of his lenders.” The president-elect’s refusal to meet the same transparency standards as every other recent inhabitant of the Oval Office, and his ascent to power at a time when foreign-reporting budgets are being slashed, suggest that the Fourth Estate will be unable to uncover all relevant conflicts.

That’s why a congressional inquiry is especially necessary.

The legislative branch cannot fulfill its constitutional duty to check and balance Trump, or provide adequate oversight of the federal agencies he presides over, without a full, accurate understanding of his business holdings and debts.

Americans ought to let their House representative and both of their senators know that they support a comprehensive inquiry into Trump’s finances. The framework at the heart of the U.S. Constitution is weakened if legislators elected to advance the public’s interests haven’t even figured out when and where it diverges from the interests of the executive-branch official they’re supposed to check.

Some lawmakers understand this.

On November 14, Representative Elijah Cummings, a Democrat on the House Committee on Oversight and Government Reform, called for a review of the president-elect’s business ties. Because Republicans will control both the House and the Senate, he is forced to appeal to Representative Jason Chaffetz, the Utah Republican who chairs the committee; it now falls to GOP leaders in Congress to exercise zealous oversight of a Republican president, requiring them to put constitutional responsibilities ahead of partisan loyalty.

You’d think strict GOP oversight here would be a no-brainer, given the GOP’s denunciation of conflicts of interest that Hillary Clinton courted while operating as secretary of state even as the Clinton Foundation made money from foreign governments.

On August 25, 2016, Chaffetz sent a letter to Secretary of State John Kerry lamenting “a perception,” created by the Clinton Foundation, “that access to our State Department’s official resources were for sale.” He was right to raise questions.

Chaffetz included questions aimed at understanding whether anything untoward occurred. If his oversight responsibilities, as he conceives them, included probing how a secretary of state with a global nonprofit might undermine trust in government or affect policy, surely he must concede that a president with for-profit businesses spanning as many countries should be as thoroughly scrutinized. Whether  Chaffetz puts country or party first will be especially easy to discern.

Justin Amash, a Michigan Republican, is already passing that test in his public pronouncements, confronting the president-elect directly over his business conflicts:

The invocation of “drain the swamp,” a Trump campaign slogan, highlights the way in which persuasive allegations of cronyism and corruption could prove especially damaging to Trump’s popularity over the long run. A man who owes much of his support to disgust with Washington insiders lining their pockets and selling out America to foreign countries cannot retain all of his supporters if he’s shown to put his own deliberately hidden foreign business interests ahead of his country.

Some citizens are already calling for congressional action:

But will enough Americans contact their representatives to demand that they adequately oversee the president-elect’s ties to foreign nations to sway some of them to actually do so?