In the early summer, when the race for the Democratic presidential nomination was just taking shape, polls painted a predictable picture: Hillary Clinton looked like a prohibitive frontrunner, with two-to-one advantages over her closest rivals.

But in the months that followed, the dynamic changed considerably. Bernie Sanders started drawing massive crowds; the press became fascinated with email server management; Democratic insiders started feeling awfully nervous; and Clinton’s poll numbers slipped. Surveys that showed the former Secretary of State dominating her competitors suddenly found Clinton with increasingly narrow leads.

Now, however, the race is starting to shift back in her direction. Consider the new NBC News/Wall Street Journal poll , for example.

1. Hillary Clinton: 62% (up four points since October, and up nine points since September)

2. Bernie Sanders: 31% (down two points since October, and down seven points since September)

3. Martin O’Malley: 3% (up from 1% in previous polling)

This is the first time Clinton has had a two-to-one edge over Sanders since July.

Also note the latest Public Policy Polling results out of Iowa:

1. Hillary Clinton: 57% (up 13 points since September)

2. Bernie Sanders: 25% (up three points)

3. Martin O’Malley: 7% (up two points)

A few months ago, several Iowa polls showed Clinton’s lead over Sanders shrinking to single digits. Over the last week, however, three separate Hawkeye State polls have found her with advantages of at least 30 points.

There’s no great mystery behind the shift.

Sanders didn’t do anything wrong – on the contrary, his recent debate performance was quite well received – but Clinton benefited from both the debate and the 11-hour Benghazi hearing, in which Republicans who intended to tear the candidate down actually did her an enormous favor.

Over the course of one mind-numbing half-day, far-right members of Congress managed to not only elevate Clinton, they also helped end interest in the odd email “controversy,” all while persuading center-left voters to rally to Clinton’s defense.

All of a sudden, her poll numbers have improved, her fundraising is up, and Democratic insiders have stopped wringing their hands and started applauding.