The political world is stuck in the middle of an accelerating protocol crisis. All sorts of customary acts of self-restraint are being washed away. It used to be that senators didn’t go out campaigning against one another. It used to be they didn’t filibuster except in rare circumstances. It used to be they didn’t block presidential nominations routinely.

It used to be that presidents didn’t push the limits of executive authority by redefining the residency status of millions of people without congressional approval. It used to be that presidents didn’t go out negotiating arms control treaties in a way that doesn’t require Senate ratification. It used to be that senators didn’t write letters to hostile nations while their own president was negotiating with them.

All the informal self-restraints that softened the brutality of politics are being torn away. It’s like going to a dinner party where all the little customs of politeness are gone and everything is just grab what you can when you can.

Into this state of affairs walks Hillary Clinton. She has, maybe more than anybody else, been shaped by this sort of political warfare. Her career has been marked by a series of brutal confrontations: Whitewater, Travelgate, health care reform, cattle futures, Monica Lewinsky, Benghazi, the emails and so on.

Her manner amid these battles is well established. In normal times, she comes across as a warm, thoughtful, pragmatic and highly intelligent person. But she has been extremely quick to go into battle mode. When she is in that mode, the descriptions from people who know her are pretty much the same, crisis after crisis: hunkered down, steely, scornful and secretive. It is said that she demands extraordinary loyalty from her troops. In the 2008 campaign, she narrowed her circle of trust to a tiny and insular set of advisers. It is said that she assumes that the news media is operating in bad faith, that the press swarms are not there for information but just to tear people down.

So one big question this year is: What happens when Hillary Clinton’s battle mode temperament hits politics as it’s currently practiced?

Since Watergate, many scandal wars have been fought over access to information about the scandal rather than about the scandal itself. In the 1970s, a series of extremely stupid sunshine laws were put into place that semi-exposed the private deliberations of public figures, distorted internal debate and pushed real conversations deeper into the shadows. Now every hint of scandal is surrounded by an elaborate tussle over who gets to see what.

These struggles over information have brought out Clinton’s most aggressive and sometimes self-destructive instincts . even when the underlying scandal was not that bad. During Whitewater, she insisted that some of her law firm’s billing records could not be found (until they were discovered in the White House residence two years after being subpoenaed). Her health care reform effort was needlessly marred by her unwillingness to release the names of her consultants. The fallout from the attack of an American compound in Benghazi, Libya, was an overblown scandal, but the State Department still withheld emails from congressional investigators.

In these cases, Clinton’s admirable respect for privacy shifted into a generalized atmosphere of hostility. It will be interesting in the months ahead to see if she continues to react to political stress in the same way. More specifically, it will be interesting to see if goes strong or goes large.

If she goes strong, she will fight fire with fire. If she is hit, she’ll hit back. She’ll treat information as a source of power to be hoarded and controlled. She’ll strap on armor each morning and go into each day strictly disciplined . ready to prove that this woman is tough enough to be president.

If she goes large, she’ll resist the urge to fight scorn with scorn. Temperamentally, she’ll have to rise above the bitterness, as Reagan, F.D.R. and Lincoln did. She and her staff will recall that the primary mission is not to win the news cycle by hitting back at whatever loon is hitting her. It’s to craft a government agenda that can win the steady support of 61 senators. It’s to win a governing majority.

The only way to reverse the protocol crisis is to create policies that can win bipartisan support. If the next president gets the substance right, the manners will follow.

Can Hillary Clinton do this? Is she strong enough to rise above hostility, to instead reveal scary and vulnerable parts of herself so that voters feel as though they can trust and relate to her? We’ll see.

Frances Perkins, a hero of mine who was F.D.R.’s secretary of labor, was one of the nation’s great public servants. But she was too reticent, too closed in her attitude toward information. She shut down in the face of the media. This attitude did her enormous harm, regardless of her many other gifts.