In this Oct. 18, 2011, file photo, then-Secretary of State Hillary Rodham Clinton checks her Blackberry from a desk inside a C-17 military plane. (Kevin Lamarque/AP)

A PARAMOUNT test for those running for president is how they make decisions — how they absorb information, what principles they carry and how it is all processed to a final choice. This is highly subjective, often lost in the hurly-burly of campaigning, but crucial. Hillary Rodham Clinton, who is expected to announce her candidacy soon for the Democratic nomination, is at one of those revelatory moments and so far seems not to have recognized it. On Monday, people in her circle suggested that she will soon answer questions about her e-mail account. We hope she seizes the opportunity to be forthcoming.

A week has passed since the disclosure that Ms. Clinton used a private account for all of her e-mail messages while serving as secretary of state, contrary to the administration’s instruction that officials should use government e-mail accounts and contrary to what the State Department — on her watch — was telling its ambassadors and other officials to do. Ms. Clinton did not turn in the e-mail records to the government when she left office. Since then, she has given the department 55,000 pages of messages in response to a request, but those were selected by her and her staff, not by government archivists or officials. All of this reveals a cavalier attitude to the public’s legitimate claim on government records.

In the past week, Ms. Clinton has said exactly this, in a tweet: “I want the public to see my email. I asked State to release them. They said they will review them for release as soon as possible.”

This perfunctory statement is even less helpful than it sounds. Ms. Clinton must know that the State Department will follow the Freedom of Information Act process to release her e-mails, requiring that they be scrutinized for sensitive information and that other agencies be consulted — a lengthy process, not likely to result in release any time soon.

The tweet also does not address a number of questions that Ms. Clinton should answer: Why did she use a private account? What discussions did she have with advisers and other State Department or White House officials about it? How many messages, if any, have been omitted from those turned over to the department? Will she permit a neutral arbiter — say, from the National Archives — to examine any withheld messages?

Some have portrayed the e-mail story as a conflict between Ms. Clinton and members of Congress who are investigating the attack on a U.S. mission in Benghazi, Libya, while she was secretary. But this is not primarily about Benghazi. Instead, it is about how Ms. Clinton responds to legitimate questions about her judgment and her record; it is about how she would function as president. Dispatching friendly politicians and former aides to television news shows to dismiss the issue as just politics does not help her cause. If she is elected president, can Americans expect a similar response when she faces difficult questions — one 26-word tweet and a cloud of obfuscation from her friends?

If she wants to demonstrate the strength of character and judgment required to be president, Ms. Clinton should hold a news conference and answer all the unanswered questions about her e-mails.