(CNN) During his meeting with The New York Times, President-elect Donald Trump sent shivers down the spines of many observers when he announced that, "The law's totally on my side, the President can't have a conflict of interest."

The comment instantly recalled the infamous remark that former President Richard Nixon made to David Frost in 1977, three years after Nixon resigned in the midst of a scandal. "When the President does it, that means it is not illegal," he told Frost. Trump's early attitude about the prestigious office he will hold brings back unsettling memories of Nixon, who didn't see the boundaries of the institution he governed.

Indeed, the first weeks since the election have raised all sorts of concerns . While Trump spent much of his campaign blasting the Clinton Foundation as some big pay-to-play scheme, Trump has been defiant in his insistence that he has the right to let his children run his international business and that he has no plan to create any kind of serious firewall. Ivanka Trump sat in on a meeting with the Japanese Prime Minister and there have been numerous reports that Trump has brought up business issues in his meetings with several foreign leaders.

Although he stormed into office promising to drain the swamp, it looks like Trump might fill the swamp with much more muck than his supporters expected. Will the White House become the headquarters of Trump Inc.? Trump has enjoyed free continuous advertising as the media films potential Cabinet picks coming in and out of his different properties.

Many Americans are surprised to learn that ethics rules do not create legal prohibitions against the president continuing to conduct his business.

We have learned a great deal about the Imperial Presidency. Now we have the Imperial Marketer.

He has exhibited a thirst for power in other ways, as well. He lashed out at the news media, both through Twitter and in person, displaying an aggressive stance toward the Fourth Estate that could create an atmosphere of hostility and intimidation that scares reporters about their jobs. Reporters should feel comfortable pursuing their stories without fearing that a president will go on a personal twitter attack against them or create pressure on a news organization to move onto different subjects.

We can't afford to see the kind of "Enemies List" that President Nixon's advisers maintained of opponents, which included journalists like Daniel Schorr of CBS and columnist Mary McGrory. Journalists should not encounter hostile crowds who are egged on by a politician blasting the "rigged media," as occurred in the campaign.

The editors, producers and owners of the organizations' reporters should not feel that presidents could possibly make policy decisions that affect them as retribution for a story.

Given what we know about Trump, it will be absolutely essential for every institution which has the responsibility of oversight to fulfill its mission of being a safeguard against presidential abuse.

The media will certainly be one central guardian of the public good. When it does its job well, it can serve as the front line in monitoring against the abuse of power by leaders in Washington.

CBS's Edward R. Murrow, one of the greatest journalists of the 1940s and 1950s, famously took on Sen. Joseph McCarthy, who was throwing around all sorts of accusations about Americans he claimed allegedly working for the communists. In 1954, using McCarthy's own words against him, Murrow went on the air to expose the senator's lies and contradictions. Washington Post reporters Carl Bernstein and Bob Woodward became legends in the mid-1970s for their work uncovering the Watergate scandal and the myriad ways the Nixon administration broke laws.

In more recent years, we saw a number of courageous journalists expose the underside of the war on terrorism, ranging from the use of torture under President George W. Bush to the intensification of targeted killings, including the assassination of a US citizen, under President Obama.

Although the press today comes under constant attack, many journalists continued to do great work on the campaign trail. The Washington Post's David Fahrenthold has published a number of hard-hitting pieces about Trump's questionable philanthropic foundation and CNN's Jake Tapper has engaged in many hard-hitting interviews with Trump and his supporters about their connections to white nationalists.

Now that Trump is in power, the press has an enormous set of responsibilities. They will have to avoid letting the President control the news story, as often occurred during the campaign, by covering each one of his controversial tweets and statements. They will have to offer viewers and readers hard-hitting analysis of the connections between his business deals and his political decision-making. They will need to carefully monitor the ways that he employs executive power and remain firm even if the administration accelerates its attacks on the media.

But the media cannot do this alone. That's why we have so many institutions that are responsible for overseeing the executive branch. Congress can't be passive on this front, even if the Republican majority will have little interest in causing problems for their own party.

In addition to the famous Watergate hearings that exposed how the break-in at the Democratic National Committee headquarters was only the tip of the iceberg in a White House that saw no limits to its power, congressional hearings have often been a powerful force for exposing the wrongdoing of a president.

In 1987, for example, a joint committee uncovered the ways in which top members of President Reagan's administration used the money from arms sales to Iran to finance the Nicaraguan Contras, despite a congressional ban on doing so. Congress, of course, reserves the power to impeach the president, and it has exercised that power several times in US history, most recently with President Bill Clinton.

Even though the Republicans control Congress, the congressional minority still has a bully pulpit and can exert pressure on the GOP to deal with issues that emerge. They will have to show the same kind of tough stance that Republicans adopted between 2007 and 2011, when they were in the minority.

Unless the Republicans do away with the filibuster altogether, Senate Democrats will still have leverage in the upper chamber to obtain concessions from Senate Majority Leader Mitch McConnell.

Given some of the hesitation about Trump that lingers within his own party, and will continue, particularly if he backs away from core promises, Democrats may well exploit these tensions if there is evidence of an abuse of power. Some Republicans, like Kentucky Sen. Rand Paul, might be open to working with Democrats on these sorts of issues if evidence emerges of abuses of power.

There has already been discussion about how the Emoluments Clause in the Constitution could become a significant problem for Trump if his business is compensated for labor or services from companies that are controlled by foreign governments.

When President Obama received the Nobel Prize, the Department of Justice determined that the law applied to the President (though they concluded he could receive the prize since the Norwegian government did not control the committee granting it and it was privately financed).

"Whenever Mr. Trump receives anything from a foreign sovereign, to the extent that it's not an arm's length transaction," said one ethics lawyer who worked in the Obama administration, "every dollar in excess that they pay over the fair market price will be a dollar paid in violation of the Emoluments Clause and will be a present to Mr. Trump."

Then there are the courts. We don't have to look far to see what the courts can do. During the past eight years, President Obama has learned how powerful they can be in tying up the executive actions of the commander in chief. Frustrated with legislative gridlock, President Obama hesitantly turned to the power of his office to move forward on key issues. He often found himself checked by the courts.

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In June, the Supreme Court announced that it was deadlocked on his plan to protect about 5 million undocumented immigrants from being deported. Their deadlock stopped the plan. "Seldom have the hopes of so many been crushed by so few words," lamented Walter Dellinger, a Duke University law professor.

Liberals will have to replicate the work of conservative organizations that have been effective at mounting concerted legal challenges against Obama's efforts to exercise executive power. The courts will have to be responsive to these concerns. Given that the Supreme Court will likely tilt back to the right after the first Trump appointment, it will be incumbent on Chief Justice John Roberts to encourage his colleagues to be extraordinarily vigilant on this front.

Although the Supreme Court remains without a justice, Obama has had more success filling the lower courts with appointees more likely to side with stances favored by Democrats.

The threat of presidential abuse of power is very real with President-elect Trump. Those fears are not a product of partisan concern, but based on the words he has used, the threats that he has made against his opponents, and the general tenor of his comments about the presidency.

As Trump has said repeatedly, Americans distrust government and they don't like the way in which politicians abuse their authority. So, given his own warnings, now is the time to make sure that he does not do more of the same.