There was a time when conservatives ran against Washington, D.C., but Republican Sen. Rick Santorum, in fighting the challenge by state Treasurer Bob Casey this year, has a problem doing that. He is Washington, D.C.

More precisely, the 12-year incumbent is the sort of calculating politician who has made the 109th Congress the out-of-touch and ethics-challenged institution that has added to the store of public cynicism.

Whatever may be said about his politics, when he was elected to the House of Representatives in 1990 and won his Senate seat in 1994, Mr. Santorum was the brash and reform-minded upstart. Today all that can be fairly said is that he is still brash, but the upstart now has settled into the role of a big man in the ruling establishment.

For all his talk of being just "an Italian kid from a steel town," Mr. Santorum, 48, was entirely in character when he was playing happy host every week to well-heeled corporate lobbyists of K Street seeking to shape the public's business in ways denied to ordinary people. That is what he has become.

To be sure, Mr. Santorum has his principles, but usually they take the form of some narrow moralizing that reduce the choices of those in a minority -- gays who want the freedom to marry and so live regular lives, women who are in a jam and feel they must have an abortion.

Some good people share Mr. Santorum's views on these issues, and actually Democrat Bob Casey, 46, is one of them, but Mr. Santorum, unlike his opponent, finds it hard to disagree without being contemptuous. It is his nature. His politics are not about uniting but dividing.

His supporters count his culture-warrior belligerence as a virtue. He speaks his mind, they say, and you know where you are with him. But far from being a brave resister of political correctness, the senator knows who his friends are and plays to them.

The latest example is the immigration issue. Illegal immigrants are not the first problem on the minds of Pennsylvanians, but it's a perfect issue for Sen. Santorum. He has a convenient scapegoat to beat upon and he can finally take a different stand than President Bush, a rare event indeed. But did Mr. Santorum do much in his years in Congress to address the problem of porous borders before the issue became hot? Of course not.

On the debacle in Iraq, Mr. Santorum doesn't get the fact that respected members of his own party are beginning to recognize the morass that is sucking the United States down even as it emboldens the terrorists.

Mr. Casey is not so far apart from Mr. Santorum on Iraq -- neither is for cutting and running -- but the Democrat at least faces facts and is thoughtful. He doesn't think the way to win the war on terror is to follow blindly a president who has seriously lost his way.

Sen. Santorum has a bigger problem. This self-described fighter has a black belt in hypocrisy. The issue of his non-residence in Pennsylvania is rooted in his slamming of Rep. Doug Walgren 16 years ago for moving to Washington, D.C. The hypocrisy got worse when Mr. Santorum, the alleged champion of taxpayers, stuck the public for the bill to educate his children in a cyber school when his residence in Penn Hills is just a legal fiction.

As much as there is wrong about Rick Santorum, there is much right about Bob Casey. Although both are social conservatives -- pro-gun, pro-death penalty, anti-abortion -- they are not to be confused on issues such as Social Security, health care and the minimum wage, issues very dear to many Pennsylvanians.

Mr. Casey would never have led the charge to privatize Social Security, as Mr. Santorum did. This was not a reform but a sure way to kill the system prematurely. (When seniors figured this out, Mr. Santorum quickly covered his tracks by proposing a bogus bill that he said would guarantee them benefits if it were privatized; it went nowhere.)

Mr. Casey would have voted for raising the federal minimum wage, which has been stuck at $5.15 an hour since 1997 and, being so low, long ago made ridiculous any arguments that job creation would be seriously discouraged. Sen. Santorum has repeatedly voted against raising the minimum wage even as he has voted, along with his colleagues, to raise his own salary.

As for health care, Mr. Casey recognizes that millions of Americans are uninsured and has proposed several remedies. Mr. Santorum fiddles around the fringes, but he and his party won't ever solve the problem. Their priorities are elsewhere.

The differences between these two men are about substance and style -- the difference between ideology and reasonableness, between the loudly harsh and the quietly decent.

Mr. Casey is a known quantity to Pennsylvanians. The son of a beloved governor, he is a career politician, too, but his record as both auditor general and treasurer has been about public service in its best sense, not about the power. And he is no hypocrite.

It is true that Rick Santorum has done some good things for Pittsburgh -- witness his efforts on behalf of saving the 911th Airlift Wing at the airport and his support for building two stadiums and a convention center for Pittsburgh -- but Mr. Casey would do those things, too.

The fact is that the kid from the steel town has left to become something else. On Nov. 7, the folks back home should hold him accountable by voting for an eminently capable and good-hearted replacement, Bob Casey Jr.