Arlen Specter has come full circle

WASHINGTON — When Arlen Specter ran for Philadelphia district attorney in 1965, he proudly proclaimed himself a "Kennedy Democrat," and said he was running as a Republican to take on what he saw as the corruption of the city's then-legendary Democratic machine.

Forty-four years later, Arlen Specter has come full circle.

In announcing his switch to the Democratic Party on Tuesday, the maverick Pennsylvanian was doing more than trying to save a political career jeopardized by the increasing conservatism of the Republican Party. He was also ratifying a decisive shift in American politics.

The GOP in his home state had once been a bastion of moderates and liberals including William Scranton, Hugh Scott and Richard Schweiker. In the age of Barack Obama, Republicans of that stripe are flooding into the Democratic Party. Specter is not a leading indicator. His conversion is the culmination of an inexorable trend.

In a sense, Specter's departure is a victory for conservatives who, since the days of Barry Goldwater, have been intent on purging liberals from the GOP. The raw political fact is that Specter was in grave danger of losing a Republican primary to former Rep. Pat Toomey, an anti-tax activist. One Democratic strategist reported seeing polling that showed Specter less popular among Pennsylvania Republicans than President Obama.

Conservatives had once hoped that creating an ideologically pure party would put them on the path to a majority. But they must now worry that the Republicans' continued rightward drift is putting the party at odds with a moderate to liberal mood that pervades the country almost everywhere outside the Deep South. And Specter's switch would give the Democrats a filibuster-proof majority in the Senate, assuming that Minnesota's Al Franken eventually takes the seat for which he now leads after an extended recount.

At the instant of his conversion, Specter transformed himself from a political underdog into a favorite for re-election in 2010. That's because Pennsylvania became far more Democratic in the final years of George W. Bush's presidency. In 2004, Democrat John Kerry carried the state by roughly 144,000 votes. Barack Obama's margin in 2008 was more than 620,000. According to the network exit polls, Democrats went from a two-point advantage in party identification in 2004 to a seven-point lead in 2008.

Reflecting a trend across the Northeast and Midwest, Democrats have posted especially strong gains in the suburbs, particularly in the counties around Philadelphia. They had once provided a base for moderate Republicans — notably Specter himself. They are now helping to pad Democratic margins, and Specter is hoping they will support him in his new political incarnation.

The agony of moderate Republicanism was reflected in Specter's efforts to appease his party's primary electorate over the last few months, even as he tried to maintain an independent stance that had served him well in general elections. It was as if he was trying to solve a simultaneous equation for which there was no answer.

At the beginning of the year, for example, he pleased Democrats and angered Republicans by backing a compromise stimulus package sought by Obama. But in the course of the negotiations, he annoyed Democrats by insisting that the package be held below $790 billion.

Specter had long received help from the labor movement. Indeed, the unions encouraged some of their members to switch parties in 2004 when Toomey challenged Specter in a primary the first time. But this year, Specter enraged union leaders when he said he could not support their central legislative goal, the Employee Free Choice Act, which would make it easier for labor organizations to sign up new members.

Specter, once a master of the ideological two-step, found himself tripping again and again in the new political environment.

And so he finds himself back where he started his political life. A man always attuned to the direction of the political winds, Specter has signaled that they are clearly blowing the Democrats' way. A politician always ready to surprise and confound his political adversaries, Specter now finds the party of Obama as appealing as long ago he found the party of John F. Kennedy. And Specter could not resist paraphrasing Kennedy in declaring that "sometimes party asks too much."

His decision reflects his own personal needs, but it also stands as a warning to the party he once embraced and has now abandoned.

E.J. Dionne's column appears regularly on editorial pages of The Times. His e-mail address is ejdionne@washpost.com