Senator Elizabeth Warren, a Democrat from Massachusetts, left, looks on as U.S. Secretary of State Hillary Clinton speaks during a Senate Foreign Relations Committee nomination hearing in Washington, D.C., U.S., on Thursday, Jan. 24, 2013. Senator John Kerry stressed the need to prevent Iran from acquiring nuclear weapons. He described the 'immediate, dangerous challenges' facing the nation as he seeks confirmation to become secretary of state. Photographer: Andrew Harrer/Bloomberg via Getty Images

Hillary Clinton has been fielding questions for months about her Wall Street speaking fees and campaign contributions, in every interview, town hall, and debate. And rightly so; we all know how the banks' fraudulent behavior tanked the economy, and everyone - Left, Right, and Center - is disgusted with what Citizens United has done to campaign finance. Clinton's defense has become streamlined and simple: sure, she took money from banks, but so did Obama - and he still passed very strict regulation on the banks. It seems effective; but there's a huge problem with this argument - so huge, in fact, that it transforms it from a defense into a powerful critique. To understand why, we turn to Sen. Elizabeth Warren (D-Mass).

Warren recently published a report, titled Rigged Justice: 2016; How Weak Enforcement Lets Corporate Offenders Off Easy. She published an editorial at the same time, in which she outlines and interprets her findings. She starts off by referring to candidates "feverishly pitching their legislative agendas." As she shows, however, laws don't mean anything if they aren't enforced -- and it turns out, in far too many cases, they effectively haven't been. Here's Warren:

In a single year, in case after case, across many sectors of the economy, federal agencies caught big companies breaking the law -- defrauding taxpayers, covering up deadly safety problems, even precipitating the financial collapse in 2008 -- and let them off the hook with barely a slap on the wrist. Often, companies paid meager fines, which some will try to write off as a tax deduction.

In fact, under Obama not a single Wall Street CEO has been prosecuted for fraud. She goes on:

These enforcement failures demean our principles. They also represent missed opportunities to address some of the nation's most pressing challenges. Consider just two areas -- college affordability and health care -- where robust enforcement of current law could help millions of people.

After giving an example of failed enforcement in each, and then one more in banking, she goes on:

Presidents don't control most day-to-day enforcement decisions, but they do nominate the heads of all the agencies, and these choices make all the difference.

(Emphasis mine). She cites examples of agencies which, under strong leadership, have truly served the public good, then another example where weak leadership has failed to. Finally, she concludes:

Each of these government divisions is headed by someone nominated by the president and confirmed by the Senate. The lesson is clear: Personnel is policy.

It is so simple that it is obvious once she has pointed it out; and yet most people rarely, if ever, consider the impact of presidential nominations - and of late they have likely done so only because Warren blocked a nominee over their strong ties to the industry they were to police. It's clear, these are the kinds of regulators who don't regulate - and don't prosecute. Warren doesn't put it in such harsh terms, but this is a scathing indictment of the Obama administration. If there were any question about why Obama has not been a Progressive, it is answered here.

Warren closes:

Legislative agendas matter, but voters should also ask which presidential candidates they trust with the extraordinary power to choose who will fight on the front lines to enforce the laws. The next president can rebuild faith in our institutions by honoring the simple notion that nobody is above the law, but it will happen only if voters demand it.

Which brings us back to Clinton, and her defense.

It is true, Obama passed strong Wall Street reform; but under his watch not a single Wall Street CEO has been prosecuted, and regulation has been lax. Do we believe Clinton might also pass strong laws? Maybe so; but Warren has proven that the laws are meaningless if they go unenforced. The real question is, would Clinton nominate strong regulators? If we judge her by Obama - as she has repeatedly insisted we should - we must conclude that she would not. In fact, Warren may just have revealed how those massive donations and speaking fees get repaid: by putting the foxes in charge of the henhouse.

By comparison, Bernie Sanders has never taken big money from any industry or individual; he has campaigned so successfully in part for that reason. Could we trust him to nominate strong regulators? Not just his current campaign, but everything about his career says we can without a doubt count on him to do so - as Warren knows well.

With her concluding question, Warren invites us to share her thinking process - and, with her report and her editorial, she provides us with the insights and facts to do so. She shows that we must look beyond the policy agenda to study the person, and decide who we trust. Warren still hasn't endorsed, but she has a way of telling us which candidate she supports. She, better than anyone else, understands the import of taking so much of Wall Street's money; and what it means that Sanders has never taken any from them, or from any other special interest.

The contrast truly could not be more pronounced, nor the potential impact more profound. Clinton's appeal to Obama's legislative record, in light of his administration's ineffective, lackluster enforcement, is in fact the case in point - just not the case she intended.