A chorus of top Democrats are demanding an independent prosecutor be commissioned to investigate Russian tampering with the 2016 presidential election.

Fine. By all means, let us have a comprehensive, independent probe of links between Russian officials and U.S. politicians. And while we are at it, why not investigate attempts to influence elections in general, by American as well as foreign leaders?

President Donald Trump’s firing of FBI Director James Comey this week spurred some Democrats to accuse the White House of attempting to stymie a federal investigation of Russian election tampering. Though there is no evidence the Trump campaign cooperated in any way with Moscow in doing that, the president’s foes are hoping against hope they can find something to pin on Trump.

Comey was fired for egregiously political conduct while at the FBI, of course. His behavior was simply beyond the bounds of what is acceptable. His testimony during the past week before Congress — so flawed at one point that the Justice Department had to issue a correction — prompted Trump to decide the time to fire Comey had come.

But if there is to be an independent investigator, he should look into other questions. One involves Russian payments to the Clinton Foundation as then-Secretary of State Hillary Clinton avoided blocking Moscow’s move to corner the world uranium market. Another could look into President Barack Obama’s attempt to sway an Israeli election. And, of course, there is the still-unresolved issue of Clinton’s lapses in handling government secrets that may have helped the Russians.

With all that on the table — as it should be — one wonders why on earth Democrat leaders would want a new investigation.