It irritates members of both groups when I note the similarities of the tea party movement that swept the nation in the 2010 election and the peace movement of the late 1960s and early 1970s.
But they are similar. Both movements represent the surge in political activity by hundreds of thousands, even millions, of previously uninvolved citizens.
Both movements focused on what are undeniably central, not peripheral, political issues: war and peace, the size and scope of government.
Both movements initially proclaimed themselves nonpartisan or bipartisan, but quickly channeled their efforts into one political party -- the peace movement in the Democratic Party, the tea party movement in the Republican Party.
Both movements were critical of leaders of the party they flocked to. The presidents who escalated American involvement in Vietnam were Democrats, John Kennedy and Lyndon Johnson.
Similarly, Republican George W. Bush increased federal involvement in education and sponsored the Medicare prescription drug entitlement, and Republican appropriators increased federal spending more than the tea partiers like.
Any inrush into political activity by hundreds of thousands or millions of people will bring forward a certain number of wackos, weirdoes and witches. Tea partiers, like peaceniks, beat moderate incumbents in party primaries and then lost in November. There were left-wing Christine O'Donnells 40 years ago.
But both movements also thrust forward many solid citizens with strong convictions, and some turned out to have good political instincts.
Peace activists meeting in a living room in Denver in 1972 seeking a congressional candidate passed over lawyer Jim Schroeder and settled on his lawyer wife, Pat. She won the seat and turned out to be a competent and well-known House member for 24 years and was, briefly, a non-frivolous candidate for president.
Similarly, in April 2010, a plastics manufacturer from Oshkosh named Ron Johnson decided to run for the U.S. Senate in Wisconsin. Mainstream media ignored him and focused on candidates like O'Donnell as part of its project to depict tea partiers as weirdoes. But Johnson beat a competent and hard-working three-term Democratic incumbent and is now a U.S. senator.
When new people embrace politics, they can change the nature of a great political party. From 1917 to 1968, the Democrats were the more militarily interventionist of our two parties. Since 1968, they have been the party more likely to oppose military intervention. That transformation, whatever you think of it, was the work of the peace movement.
New movements can ultimately strengthen a party, particularly one like the late 1960s Democratic Party, which saw some of its historic constituencies (Southern whites, big-city Catholics) flee its ranks. Similarly, the Republicans in 2006 and 2008 lost many voters they had registered and rallied to re-elect Bush in 2004.
But new movements prove troublesome for the political pros, and nowhere more than in the most problematic part of our political system, the presidential nominating process. (Is it just a coincidence that this is the one part of the system not mentioned at all in the Constitution?)
Peaceniks and tea partiers naturally want nominees who are true to their vision. They are ready to support newcomers and little-vetted challengers over veteran incumbents who have voted the wrong way on issues they care about.
But the things that make candidates attractive to movements can also make them unattractive to independent voters.
The Democrats struggled with this in the 1968, 1972 and 1976 cycles. The old-timers pushed through the accomplished Hubert Humphrey over the diffident Eugene McCarthy in 1968, but they lost to George McGovern in 1972. He was a more serious candidate than is generally remembered, but he did lose 49 states to Richard Nixon.
Since then, Democratic candidates have strived to meet peace movement litmus tests. Bill Clinton did so characteristically by saying that he agreed with the arguments of opponents of the 1991 Gulf War resolution but would have voted for it.
Republicans are now grappling with a similar situation. Mitt Romney is next in line, but some of his past positions are -- how to put this politely? -- in tension with those of the tea party movement. Tea party types have been scrambling to settle on an alternative, so far without success.
Tea partiers will grouse if Romney is nominated. But maybe they need patience and perseverance. One lesson of history is that a movement can reshape a party. Another is that it takes time.