Democrats have already held their caucuses in Nevada and Clinton snatched momentum there against Sanders. The challenge for Clinton is to keep it going.

In the days since her Nevada victory, Sanders has increasingly sharpened his attacks on Clinton. He picked up on an issue he’d previously dropped, with his campaign tweeting Monday about Clinton’s refusal to release her paid speeches to firms like Goldman Sachs: “It’s been 17 days, 16 hours and 32 minutes since @HillaryClinton said she would ‘look into’ releasing her paid speeches to Wall Street.”

Clinton still doesn’t have a good answer to questions about why she gave speeches to the Wall Street firms she now says she’ll be tough on — and why she won’t release the transcripts of those speeches.

It’s among the reasons exit polls show Sanders continuing to trounce Sanders on the issue of credibility.

She stumbled on the issue during the last CNN Democratic town hall. Tuesday night’s forum could show whether she has found a better way to answer those questions.