During the election, there were allegations from both sides about Russia's involvement. Some democrats say that Clinton lost because Russia somehow got involved and they were on Trump's side. In the end, Obama should declassify the documents so that the people can see for themselves. This is the best way to end the controversy.
If President Obama has clear evidence that the Russians were somehow involved in the election process, then this information should be in the public domain. The Obama administration have often been quick at pointing the finger at the Russians over various issues, but very rarely backup their claims with proof. So, if they now have concrete proof, it should be made available for all to see.
At least some of these documents should be declassified so that the general public understands what happened as far as the Russians being involved. He does not have to declassify all of the documents, particularly if some of them contain information that is included in some investigations and top secret missions that are still ongoing.
The documents on Russian involvement in the election should not be declassified for security reasons. It is important to keep control over the political and security issues that impact our country and should not be open to all citizens. This is an issue for the government and security officials to handle.