VOTER REGISRATION UNDER party labels has been on the decline for years, but new figures show political parties in Massachusetts withering at a much greater rate than previously known, with nearly two-thirds of all voters now registered without a party designation.

On a practical level, there is little benefit to registering under a party banner in Massachusetts, given the state’s semi-open primary system, where unaffiliated voters can participate in either party’s nominating contests. This has contributed to the long term decline of party rolls. But what was a steady decline of registered partisans is now a freefall due to new systems of registering voters.

If current trends continue, party registration will be so unusual that the two-party system will cease to be a useful way to group Massachusetts voters. So few voters will be registered with parties that a young registered Democrat will be an unusual sight and young Republicans will go on the endangered species list…