very straightforward message.

Warren began by speaking about a string of scandals that emerged as a result of the continued existence of "too big to fail banks." Despite this evidence and the fact that many officials have admitted the dangers to the economic system posed by big banks, Warren noted that various members of President Barack Obama's administration have appeared unwilling to prescribe concrete measures to address them. She then pointed specifically to a quote from a Treasury official during former Treasury Secretary Tim Geithner's tenure that suggested the department had been instrumental in scuttling an earlier bipartisan amendment that would have enacted restrictions on "too big to fail."

About those banks considered "too big to fail"? Warren put Lew on the hot seat.

"Have you changed your position?" Warren demanded, referring to the Treasury department. "Or are you still opposed to capping the size of banks?"

Lew responded that "ending to big to fail is our policy and we're aiming to do it." But Warren wouldn't let him weasel out of the question with generalities. "I want to focus you in here," she pushed. "My question is about capping the size of largest financial institutions."

Lew refused to commit. "Our job right now is to implement … Dodd-Frank," he said. "I think this is not the time to be enacting big changes."

"Let me try the question a different way," Warren persisted. "How big do the biggest banks have to get before we consider breaking them up?" she asked, adding that the largest American banks are 30 percent larger than they were five years ago. "Do they have to double in size? Triple in size? Quadruple in size? Before we talk about breaking up the biggest financial institutions?"

Lew said that too big to fail "is an unacceptable policy", but urged Warren to have some patience.

She'd have none of Lew's excuses: "What we've seen… is one scandal after another in these largest financial institutions," she said. "It's clear they have not changed their risk bearing practices nor have they decided that they're suddenly going to start following the law."

Shorter Senator Warren to Treasury Secretary Jack Lew: Do a better job of reining in the bastard demons of the financial world than your predecessor, or the good Senator will pin him to the wall like a butterfly over the ease with which banks slither away from any consequences of their wrongdoing.