As Hillary Clinton returns to Iowa on Monday, a sense of anxiety is cascading through her campaign, with an increasing sense of urgency the primary fight with Bernie Sanders is far more of a threat than once imagined, unlikely to be extinguished after the first contests in Iowa and New Hampshire.

Clinton has gone from all but ignoring Sanders to fiercely engaging him in recent days, a reflection of public and private polling that points to a race that is uncomfortably competitive for the Democratic front-runner. She openly questions his electability and argues that he is out of step with the party on guns and other issues.

But there are fresh questions about her electability argument, with Sanders faring better than Clinton in a series of hypothetical head-to-head matchups with top Republicans in Iowa and New Hampshire, according to the latest NBC/Wall Street Journal/Marist poll. Sanders holds a double-digit edge over Trump in both states, for example, while Clinton has a far narrower lead.

Still, Clinton is hoping to persuade voters who may be intrigued by Sanders’ populist rage to take a longer view and embrace her candidacy, whether or not they were initially enthused.

Read the article “Hillary Clinton Increasingly Anxious About Bernie Sanders” on cnn.com.