Elizabeth Warren’s memoir begins with the story of a family in collapse. She was 12 years old when her father had a heart attack.

His recovery was slow. Unable to work, the family’s finances tanked. The Studebaker was repossessed. When he was able to return to work, Montgomery Ward took away his job selling carpeting and gave him a job selling lawn mowers on commission. Warren asked her mother why the old job was gone. “In her view, his company had robbed him of something he’d worked for. And now, she said, ‘They think he’s going to die.’ ”

The financial spiral had the predictable effect on the family’s emotional life. “Sometimes that spring I would overhear my parents arguing,” Warren remembers, “I guess I shouldn’t describe it as arguing; my father never said much of anything, while my mother yelled louder. They drank more, a lot more. . . . I knew that my mother blamed my daddy for not doing ‘what a man is supposed to do’ and taking care of us.”

Her mother ended up getting a job at Sears, her father got a job as a maintenance man and the family finances stabilized . at a low level. Warren concluded the episode this way: “My mother never had it easy. She fought for everything she and my daddy ever had.”

The memoir is called “A Fighting Chance.” The words “fight” or “fighting” appear in the book 224 times. In high school, Warren writes, she couldn’t play a musical instrument or a sport, “but I did have one talent. I could fight . not with my fists, but with my words. I was the anchor on the debate team.” Of her tennis game she writes, “Once I had a weapon in my hand, I gave it everything I had.”

With relish, she describes a fight she later had with a judge on a panel discussion over bankruptcy law. “The judge probably had a hundred pounds on me, and he started shifting himself closer to the microphone and edging me out of his way. I grabbed the table for leverage and pushed my way to the microphone, going shoulder to shoulder with the judge as I hit back with arguments. . . . I glanced over and noticed with satisfaction that the veins in his neck were throbbing and his face was red and sweating. I wondered briefly whether he might have a stroke right there on the small stage.”

Her biggest adult fight has been against the banks, against what she saw as their rapacious exploitation of the poor and vulnerable. The crucial distinction Warren makes is this one: It’s not just social conditions like globalization and technological change that threaten the middle class. It’s an active conspiracy by the rich and powerful. The game is rigged. The proper response is not just policy-making; it’s indignation and combat.

The political class has been wondering if Warren, a United States senator from Massachusetts, will take on Hillary Clinton for the Democratic presidential nomination. This speculation is usually based on the premise that Warren couldn’t actually win, but that she could move the party in her direction. But, today, even for those of us who disagree with Warren fundamentally, it seems clear that she does have a significant and growing chance of being nominated.

Her chances are rising because of that word “fight.” The emotional register of the Democratic Party is growing more combative. There’s an underlying and sometimes vituperative sense of frustration toward President Obama, and especially his supposed inability to go to the mat.

Events like the Brown case in Ferguson and the Garner case in New York have raised indignation levels across the progressive spectrum. Judging by recent polls, the midterm defeat has not scared Democrats into supporting the safe option; it’s made them angrier about the whole system. As the party slips more into opposition status, with the next Congress, this aggressive outsider spirit will only grow.

In this era of bad feelings, parties are organized more around what they oppose rather than what they are for. Republicans are against government. Democrats are coalescing around opposition to Wall Street and corporate power. In 2001, 51 percent of Democrats were dissatisfied with the rise of corporate power, according to Gallup surveys. By 2011, 79 percent of Democrats were. According to an NBC News/Wall Street Journal poll last month, 58 percent of Democrats said they believed that the economic and political systems were stacked against them.

Clinton is obviously tough, but she just can’t speak with a clear voice against Wall Street and Washington insiders. Warren’s wing shows increasing passion and strength, both in opposing certain Obama nominees and in last week’s budget fight.

The history of populist candidates is that they never actually get the nomination. The establishment wins. That’s still likely. But there is something in the air. The fundamental truth is that every structural and historical advantage favors Clinton, but every day more Democrats embrace the emotion and view defined by Warren.