The Republican plan to end Medicare and replace it with a voucher plan is deeply, deeply unpopular. It helped cost them an otherwise safe Republican seat in NY-26. So the House GOP is reacting in a sane, grown-up fashion: it’s blocking House Democrats from using their franking privilege to accurately inform their constituents about what the Teapublicans have in store for them.
Generally the Republicans are skilled both at cheating and at getting away with it. But in this case, the Democratic response is almost too easy. If I were one of the censored Dems, I’d submit a new mailing, this one asking my constituents to protest the censorship, and quoting the full passage in dispute.
Footnote: No, the Republican tu quoque doesn’t connect. Obamacare is not, in fact, a “government takeover” of health care. That’s not a question on which opinions can legitimately differ, it’s just a matter of fact. Equally clearly, the Ryan plan does end Medicare, replacing it with an utterly different program with the same name.