The Trump administration might not want such an investigation, though, for reasons having nothing to do with the substance of any discussions with Russian officials. Investigations inevitably metastasize, and draw attention away from an administration’s substantive agenda. In today’s hyper-partisan climate, it’s even more likely that a GOP-led investigation that came up empty would simply be dismissed as part of a coverup.

Individual members of Congress, meanwhile, might support or oppose an investigation for reasons that have nothing to do with the substance of the issue. Opponents of rapprochement with Russia, for example, would have every reason to want to make continued pursuit of such a policy politically toxic.

Which is precisely why it is supporters of such a policy who should be taking the lead in calling for such an investigation.