Addressing the issue properly will require a bipartisan congressional investigation led by people with the authority and intent to get to the truth, however disturbing that might be for the incoming administration and the Republican Party. The intelligence agencies concluded that the Russian hacking was meant to help elect Mr. Trump.

Mr. McConnell and Mr. Ryan have both called for a congressional inquiry, but they want it handled by the permanent standing committees, a bad idea for practical and political reasons. A far better approach would be to establish a select committee, with both House and Senate members, that would examine the Russian hacking across many areas of expertise. Senators John McCain of Arizona, Lindsey Graham of South Carolina and Cory Gardner of Colorado, all Republicans, argue that a select committee is necessary for an investigation as complex and politically delicate as this one. So does Senator Chuck Schumer, soon to be the Senate minority leader.

Cybersecurity threats cut across the jurisdictional lines of permanent congressional committees. Such threats have been examined by at least 19 standing committees in the House and Senate, including those that focus on the work of intelligence agencies, homeland security programs and military operations. If Mr. McConnell’s approach prevails, several House and Senate committees are likely to do overlapping work. Because those investigations would be run by lawmakers with varying degrees of loyalty to the White House, their disparate conclusions would probably be seen through a political lens.

A bipartisan select committee with subpoena power could examine the Russian hack in a comprehensive, dispassionate manner, with an eye to shielding its conclusions from charges of partisanship.

“This cannot become a partisan issue,” Mr. McCain, Mr. Graham and Mr. Schumer said in a statement. “The stakes are too high for our country.”