WEDNESDAY'S news conference by Senate Intelligence Committee Chairman Richard Burr (R-N.C.) and Vice Chairman Mark R. Warner (D-Va.) raised more questions than it answered on the state of the committee's probe into Russian election interference. But it did make one thing clear: The investigation is far from over.

Updating the public on an effort that has now gone on for nine months, Mr. Burr and Mr. Warner emphasized both the volume of work they've completed thus far and the volume they have yet to do. Mr. Burr stated that the committee members "trust the conclusions" of the intelligence community's January report that the Russian government sought to undermine the integrity of the 2016 election — though he later indicated some doubt over the report's conclusion that the Kremlin supported Donald Trump over Hillary Clinton. Importantly, we learned that the committee continues to study whether collusion took place between the Kremlin and the Trump campaign. And Mr. Warner made clear that Russian efforts to create chaos are ongoing, both in the United States and in Western Europe.

To some extent, the news conference demonstrated progress. Mr. Burr pointed to areas of the investigation that are close to being wrapped up — most notably, former FBI director James B. Comey’s memos regarding his interactions with President Trump, about which the chairman stated that the probe “has reached a logical end.”

Yet Mr. Burr and Mr. Warner also cautioned that the investigation has a long way to go. Previously, Mr. Burr had indicated his hope that the committee could finish its work by the end of 2017. On Wednesday, while he hinted that he'd still like to wrap up by December, he also emphasized that the probe has become increasingly complex and that the committee will need to take its time.

Many aspects of the committee’s work remain murky, including the precise scope of its investigation. Mr. Burr’s statement that the committee has completed its work on Mr. Comey’s memos raises the question of whether Mr. Burr and Mr. Warner consider the president’s possible obstruction of the FBI probe into election interference to be within the scope of their work.

Nevertheless, Mr. Burr and Mr. Warner’s investigation remains the most serious effort besides that of special counsel Robert S. Mueller III to get to the bottom of just what happened during the 2016 election. Their news conference is an encouraging sign that the Intelligence Committee’s leaders are approaching their task seriously and without partisanship. Now, they have the responsibility to follow through and resist pressure from the White House and Mr. Trump’s allies in Congress to wrap up their investigation prematurely.

“Russian active measures did not end on Election Day,” Mr. Warner told the media, urging state election officials to fortify their systems in the coming months. His comments remind us why this investigation is so important. It’s a matter not just of uncovering a past attack on American democracy by a foreign power but also of understanding and preventing similar attacks going forward. He and Mr. Burr should take the time they need to get it right.