On December 7, Donald Trump strode out in front of the assembled television cameras and did something unusual: The stream-of-consciousness candidate read a prepared statement.

It said: "I, Donald J. Trump, am calling for a total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what the hell is going on."

Trump didn't break a law that day; he broke a norm. Major politicians can single out particular religious groups for discriminatory treatment in the United States. They just … don't.

They don't do it even when they might find votes through bigotry. The restraint isn't entirely altruistic. Norms are enforced through powerful, if informal, mechanisms in American politics — in this case, widespread condemnation from politicians of both parties, as well as (accurate) accusations of bigotry and racism.

But Trump isn't bothered by the guardrails of American politics. As I've written before, his most salient characteristic is that he operates entirely without shame. He doesn't care if he's condemned, or called a bigot, or shown to be a liar. He cares about the polls, and he cares about winning, and he sees everything else as negotiable. In this, he truly is a dealmaker: If the cost of the presidency is being seen as a racist, he'll pay it.

To understand the danger Trump poses, though, it's important to recognize what happened next. Banning all Muslims from traveling to the United States, for any reason, went instantly from being a proposal so bigoted and outlandish that no one had even considered it to a proposal at the center of the American political debate. It was discussed. It was polled. It was normalized.

Any politician looking to appeal to Trump's voters had to at least see his point. Ted Cruz, for instance, stood up in the next presidential debate to say, "I understand why Donald made that proposal," even though he went on to oppose it. Polls soon showed a majority of Republicans agreed with Trump.

Proposals to restrict Muslim travel that had looked extreme before now looked like modest compromise measures. Cruz went on to tout his legislation to "suspend all refugees for three years from countries where ISIS or al-Qaeda control substantial territory," a cruel and scary idea that he could now sell as a more "narrowly targeted" effort to solve the same problem that worried Trump. When that failed to win over Trump's voters, Cruz took it further, proposing to "patrol and secure" Muslim communities in America.

Similarly, after Trump proposed creating a federal database of Muslims living in America and shutting down mosques, Marco Rubio followed suit. He told Fox News he was for "closing down any place — whether it’s a cafe, a diner, an internet site — any place where radicals are being inspired."

This is the danger Trump poses to the American political system, even if he loses. He is normalizing the abnormal. He is redefining what is acceptable to do and say in American politics.

Many will cheer his efforts. Some will say they don't quite agree with him, but they will applaud his fearlessness — shouldn't any policy be open for discussion; shouldn't any idea be fit for the public square?

The answer, of course, is no, it should not. Americans are protected by our constitutional right to free speech. But we are also protected by norms around the kind of speech that is acceptable, particularly from those in public life.

Peter Parker, one of America's truly great theorists of the public good, likes to say that "with great power comes great responsibility." Trump has great power. But he has no sense of responsibility. And so he can do great damage.

America is a nation of norms, not just a nation of laws

Americans pride themselves on our politicians' respect for the rule of law, on the checks and balances that protect us from the powerful. But as often as not, our real protection is found not in laws but in norms.

Consider the president's pardon power. In theory, the president of the United States can pardon whomever he wants, for whatever federal crimes he wants, in whatever numbers he wants. It is, the Heritage Foundation writes, "one of the least limited powers granted to the President in the Constitution."

On January 21, 1977, for instance, President Jimmy Carter granted an unconditional pardon to all Vietnam War draft dodgers. With a stroke of his pen, Carter took an estimated 210,000 criminals and made them not-criminals.

Consider what a president could do with this power. He could pardon thugs who assault his critics. He could pardon soldiers who commit war crimes. He could pardon campaign staffers who commit crimes on his behalf. And the pardon power is occasionally misused, as in the case of Bill Clinton's pardon of Marc Rich. But the power of the pardon is rarely wielded as a way of greasing the skids for vengeance or intimidation.

On March 10, John McGraw, a 78-year-old Trump supporter, sucker-punched a black protestor at a Trump rally. The assault was caught on tape, and McGraw was unrepentant. "Yes, he deserved it," McGraw told Inside Edition. "The next time we see him, we might have to kill him."

The police promptly arrested McGraw and charged him with assault and battery and disorderly conduct.

And that might have been where the story ended, save for a vow Trump had made at an earlier rally. "I promise you, I'll pay the legal fees," he told the crowd after asking them to "knock the crap" out of any protesters who might try to throw fruit at him.

Did that promise apply to McGraw, Meet the Press host Chuck Todd asked Trump? Yes, Trump said, "I’ve actually instructed my people to look into it."

Rather than being annoyed at a supporter who made him look bad by assaulting a protester, Trump's instinct was to pay the guy's legal fees. Now consider the power of the pardon in President Trump's hands. What will he do when he needs to protect aides or allies who actually were working on his behalf, or whom he actually owes something to?

There is a rebuttal to this, of course. Yes, the president wields tremendous power if he's unrestrained by the norms of American politics. But he's still restrained by the rules of American politics. In practice, the House and Senate could impeach him for true violations of the spirit of his office.

Right. About that.

This is how norms die, by Alberto Gonzales

Even for Trump, the comment was shocking. In an interview with the Wall Street Journal, he said the judge presiding over the lawsuit against Trump University should have to recuse himself because of his "Mexican heritage." (Judge Gonzalo Curiel, it should be noted, was born in Indiana, which is now and was at the time of his birth part of the United States; his parents were born in Mexico).

"I’m building a wall," Trump said. "It’s an inherent conflict of interest."

This is actually not an inherent conflict of interest, or even any kind of conflict of interest. What it is, as German Lopez has written, is straight racism, and it's being used by a presidential candidate to delegitimize the oversight of the judiciary. It is a shocking moment.

Plenty of Republicans condemned Trump. Megyn Kelly attacked him on Fox News. Paul Ryan condemned the comments less than 24 hours after offering his endorsement. But you could also watch the gravitational pull of the Republican Party's need to rally around the party's nominee for president exert itself.

Alberto Gonzales, who served as attorney general under George W. Bush and — who knows? — could be a Supreme Court nominee for Donald Trump, was quick to throw the candidate a lifeline. "Curiel’s Mexican heritage alone would not be enough to raise a question of bias," Gonzales wrote, going on to say:

But there may be other factors to consider in determining whether Trump’s concerns about getting an impartial trial are reasonable. Curiel is, reportedly, a member of a group called La Raza Lawyers of San Diego. Trump’s aides, meanwhile, have indicated that they believe Curiel is a member of the National Council of La Raza, a vocal advocacy organization that has vigorously condemned Trump and his views on immigration. The two groups are unaffiliated, and Curiel is not a member of NCLR. But Trump may be concerned that the lawyers’ association or its members represent or support the other advocacy organization. Coupled with that question is the fact that in 2014, when he certified the class-action lawsuit against Trump, Curiel appointed the Robbins Geller law firm to represent plaintiffs. Robbins Geller has paid $675,000 in speaking fees since 2009 to Trump’s likely opponent, Hillary Clinton, and to her husband, former president Bill Clinton. Curiel appointed the firm in the case before Trump entered the presidential race, but again, it might not be unreasonable for a defendant in Trump’s position to wonder who Curiel favors in the presidential election. These circumstances, while not necessarily conclusive, at least raise a legitimate question to be considered.

Catch all that? Curiel's presence on this case predates Trump's presidential run, but he might be biased because the National Council of La Raza, a group Trump's aides say Curiel belongs to even though he actually doesn't belong to it, doesn't like Trump, and because Curiel appointed a law firm that paid Hillary Clinton to speak, even though that appointment came before Trump's run for office.

You could spend days unpacking the absurdities here, and others have. But the underlying reality is more chilling, and more obvious: As noxious as many Republicans think Trump's Curiel comments were, none have pulled their endorsements, and some have even moved to give Trump cover.

A political party has powerful reasons to protect its nominee, and even more powerful reasons to protect its president. Even if the party members disagree with his actions, they know that attacking him could lead to reprisal from either the White House or the party base, and they know impeaching him would imperil everything else they want to accomplish and trigger catastrophic losses in the next election. Ultimately, power and partisanship overwhelms principle:

Ryan says Trump remarks on judge are "textbook definition of racism."



"But do i believe Hillary clinton is the answer? No i do not." — Mike DeBonis (@mikedebonis) June 7, 2016

Paul Ryan is a good example of how this dynamic plays out. He has been as forthright in condemning Trump's comments on Curiel as anyone in office. "I disavow these comments," he said. "I regret those comments that he made. Claiming a person can't do their job because of their race is sorta the textbook definition of a racist comment. I think that should be absolutely disavowed. It's absolutely unacceptable."

But he didn't stop there. "Do I believe that Hillary Clinton is the answer? No, I do not ... [Republicans and Trump] have more common ground on the policy issues of the day, and we have more likelihood of getting our policies enacted with him than we do with her."

And what is crucial to understand here is that Ryan is right. Republicans do have more common ground with Trump than with Clinton. Ryan really is likelier to pass his budget if Trump occupies the White House, and amidst a norm-breaking presidency, he really would be likelier to keep his speakership if Republicans protect Trump from impeachment. His incentives ultimately push him to rally around Trump, as distasteful as he clearly finds the exercise.

A president who chooses to rampantly violate the norms of American politics is not likely to be checked so long as his own party holds serious power. What's worse, a president who rampantly violates the norms of American politics will drag many in his party into complete or near complicity; he will redraw the boundaries of what is acceptable in American politics.

The normal constraints, meanwhile, are failing this year. Trump does not have enough shame to check himself. His party does not have enough courage to check him. The media does not have, or see itself as having, the capability to check him. And so he will not be checked. His candidacy will demolish longstanding norms of decency, civility, and tolerance. And his presidency — well, his presidency could do much worse.

Those who comfort themselves that a Trump administration could only do so much damage because it's hard, in the American political system, to pass or repeal laws should think again. Yes, it is hard to pass or repeal laws. But it's easy to destroy norms, and a vengeful, frustrated, or simply impulsive president could do terrible damage unconstrained by the norms that limit our leaders.