Catholic Sen. Bob Casey Jr., D-Pa., is scheduled to speak at the Democratic Party’s 2008 convention. But there’s still time. He can, and should, back out.

The Democratic hierarchy has come to learn the hard way that the party is losing presidential elections because pro-lifers view it as the party of abortion. This is a well-earned reputation, one that has sent literally millions of pro-life Democrats to the Republican presidential ticket year after year.

Seeing the difference that so-called “values voters” — the pro-life, churchgoing evangelicals and Catholics — made for George W. Bush in 2000 and 2004, the Democratic Party has launched a concerted push.

Those voters could not bring themselves to vote for Sen. John Kerry, D-Ma., in 2004, who happened to be a Roman Catholic with a perfect 100% rating from the abortion lobby. In turn, the Democratic leadership, notably Sen. Harry Reid, D-Nev., and “pro-choice Catholic” U.S. Rep. Nancy Pelosi, D-Calif., began seeking pro-life Democrats who could challenge and unseat pro-life Republicans in Congress.

The most stunning example of this was the trouncing of Sen. Rick Santorum, R-Pa., by Bob Casey Jr. in 2006, costing pro-lifers their single best fighter in the U.S. Senate.

Since then, those victorious pro-life Democrats have been marginalized, dispatched to the wilderness by the party that used them to win the Senate and House, where they can push an “abortion rights” agenda. The likes of Casey have let themselves be used over and over.

Now, in the 2008 presidential race, the Democrats have an even bigger problem with the abortion issue. Sen. Barack Obama, D-Ill., is so extreme on abortion — voting in his state against medical care for babies who survive abortions — that he makes Kerry look moderate. For the Democratic leadership, this problem this time around is unnerving because conservative Christians are by and large not thrilled with Sen. John McCain, R-Ariz., the Republican nominee.

In other words, had it not been for Obama’s abortion extremism, this might otherwise be the Democrats’ year to win just enough of those “values voters” to take back the White House. And yet, Obama will not change his position on abortion at all, which is truly sacred ground for him. He made a vow to Planned Parenthood that his first action as president would be to sign a federal Freedom of Choice Act, wiping off the books state and local laws regulating abortion.

The best that Obama can do is to try to soften his rhetoric, to change his tone on the issue — rhetorical overtures at which he excels as a polished speaker and appeals to the emotions of people. The adjustment will be purely one of image, not substance. Here, Casey has already lent a hand: When Obama was campaigning in Pennsylvania during the Democratic primary in April, where he lost to Sen. Hillary Clinton, D-N.Y., by double digits, he brought along the state’s pro-life Democratic senator. Casey was there, unflinching, when, at Messiah College in Grantham, Obama refused to concede that life begins at conception, and when, in Greensburg, he expressed his dismay at how he would hate to see his daughters “punished by a baby” if they got pregnant out of wedlock. The “hope” of the Obama campaign is that the association with the presence of the likes of Casey will help change the perspective of Obama as the most extreme abortion advocate ever to lead a ticket.

But, alas, that wasn’t enough during the Pennsylvania primary in April — and it will not be enough nationally in November. As a result, someone in the Democratic National Committee has hatched a truly brilliant scheme: Obama talks tolerance, openness, newness, change, diversity. So did Bill and Hillary Clinton, but at the 1992 Democratic Convention, they infamously blocked pro-life Catholic Gov. Robert P. Casey — the late father of the current senator — from speaking. It was a troubling, telltale rejection of a good, principled man, an accurate reflection of a party closed to the pro-life perspective.

This time around, for the 2008 convention, someone has apparently floated the ingenious, Machiavellian idea of inviting the junior Casey to speak. In turn, the liberal press will run with the strategy, heralding the overture as a new day for a new, tolerant attitude for “abortion rights” by the new, tolerant Obama campaign.

As for Casey, he once again seems dutifully willing to play the role of sucker. In fact, this leads one to wonder if Obama had made the suggestion to Casey back in April as a way of winning his endorsement, of taking it away from Hillary Clinton — one of those Clintons who snubbed Casey’s father back in 1992.

Either way, Casey candidly hopes that Obama will use him. “I want to do whatever it takes to get him [Obama] over the goal line.”

The goal line to which Casey is referring is not the goal of stopping abortion, or requiring medical care for abandoned, abortion-surviving babies slowly dying of a lack of medical care — but, rather, electing Barack Obama president of the United States, where Obama would deliberately work against each and every pro-life conviction of Casey and his late father.

It isn’t too late for Casey to just say No. He should tell party leaders that when the party is ready to get serious about a general change in substance on abortion, not mere rhetoric or appearance, then he will talk at their convention, but, until then, he is not their useful idiot — and neither are those pro-life Pennsylvanians who voted for him.

Paul Kengor is professor of political science at Grove City College and author of God and Hillary Clinton (HarperCollins, 2007) and The Judge (Ignatius Press, 2007).