Not long ago, JPMorgan Chase was a sort of hero among U.S. banks. The global giant had exited the subprime mortgage market before the crash began in 2007. It entered the subsequent panic with what its chief executive, Jamie Dimon, called a “fortress balance sheet.”

Today, federal and state governments are under pressure to punish Wall Street, and JPMorgan and Dimon find themselves cast as villains. Facing multiple investigations for alleged misdeeds ranging from misrepresenting mortgage-backed securities to favoring the children of powerful officials for jobs in China, JPMorgan is being held up by critics as an example of everything wrong with the big banks. Last week it also announced the first quarterly loss of Dimon’s tenure, citing $9.2 billion in legal bills.

Indeed, the crackdown on JPMorgan has gotten so aggressive that the bank claims it now qualifies for a new status: victim.

Does it? Well, yes and no.

One matter is alleged current conduct, such as the disastrous derivative trade known as the “London Whale,” which lost the bank $6 billion, and nepotism in China, which, if proved, would be as bad as it sounds. Such cases represent appropriate subjects for the government’s legal firepower.

We’re less impressed by the more backward-looking attack on JPMorgan for allegedly misleading investors about the quality of securities it marketed before the crash. Dimon reportedly is facing a demand for $11 billion in fines and other payments to settle the case, under threat of a Justice Department criminal investigation. Yet roughly 70 percent of the securities at issue were concocted not by JPMorgan but by two institutions, Bear Stearns and Washington Mutual, that it acquired in 2008. Among the investors supposedly ripped off were the sophisticated government-sponsored enterprises known as Fannie Mae and Freddie Mac. As was inevitable, some say the case is payback for Dimon’s criticism of Obama administration policy.

We don’t take that view; nor do we pity JPMorgan, which is still a lucrative business despite its legal woes and which purchased the institutions for their valuable assets mixed in with their massive liabilities. When it bought them, it bought their legal issues, too — known and unknown.

Let’s keep emotion, pro- or anti-Wall Street, out of financial law enforcement generally. In other words, as important as the government’s reputation for toughness may be, its reputation for impartiality is more precious by far.

The Washington Post (Oct. 16)