It would have been impossible to imagine a year ago that the Republican Party’s leaders would be effectively serving as enablers of Russian interference in this country’s political system. Yet, astonishingly, that is the role the Republican Party is playing.

U.S. intelligence services have stated that the Russian government interfered in the 2016 presidential election with the intention of swinging it to one side. Knowing how cautious the intelligence community is in making such judgments, and given the significance of this particular finding, the evidence must be compelling. At the very least, any reasonable person would have to conclude that there is enough evidence to warrant a serious, wide-ranging and open investigation. Polls suggest that a majority of Americans would like to see such an investigation carried out.

It’s important at this time of intense political conflict to remain focused on the most critical issue. Whether certain individuals met with Russian officials, and whether those meetings were significant, is secondary and can eventually be sorted out. The most important question concerns Russia’s ability to manipulate U.S. elections. That is not a political issue. It is a national security issue. If the Russian government did interfere in the United States’ electoral processes last year, then it has the capacity to do so in every election going forward. This is a powerful and dangerous weapon, more than warships or tanks or bombers. Neither Russia nor any potential adversary has the power to damage the U.S. political system with weapons of war. But by creating doubts about the validity, integrity and reliability of U.S. elections, it can shake that system to its foundations.