I know this is an OP-ED, but it would be nice if you would use facts to form your opinion.
Misleading statement or lie number 1.
"Many are part of a vocal, Internet-savvy lobby that has been agitating to coerce the church's prelates into denying Communion to Catholic officeholders who deviate from a rigidly "pro-life" line."
No one is agitating prelates into denying Communion to pro-choice politicians -- Cannon Law dictates this.
Misleading statement or lie number 2.
"Made up of a number of smaller groups, this lobby has campaigned to keep other pro-choice officeholders (of any religion) from speaking at Catholic schools."
This too is official from the USCCB, that no pro-choice politician be awarded an honor or a speaking engagement. This is not some lobby effort.
Just four paragraphs in and you have two huge errors that set the tone for your OP-ED.
Paragraph 5 and we have lie number three:
"The effort turns on convincing Catholics -- for decades now, the principal swing voters in presidential elections -- that they're obliged to vote on the basis of moral issues important to the right wing of the church, such as abortion, stem cell research and, more recently, marriage equality."
Once again you're wrong, Catholics are obligated to vote this way from official Church teaching. Not the so-called right-wing, get your facts straight, man. There is no right or left wing in the Catholic Church. There are orthodox Catholics and heterodox Catholics. All official doctrine comes from Rome and Rome alone. Anyone who calls themselves a Catholic and does not adhere to official Church teaching from Rome is heterodox -- it's that simple. All those that do, are orthodox. If that's what you mean by the right-wing then you obviously know very little about Catholicism.
"The movement has attracted a handful of marginal figures among the country's Catholic bishops."
They would be the bishops that are actually doing what the USCCB agreed to -- otherwise known as "the right thing."
"The South Bend bishop, who usually attends the graduation, has said he'll boycott this year's ceremony."
Once again, according the the official document of June 2004, Catholics in Political Life, the bishops said, “The Catholic community and Catholic institutions should not honor those who act in defiance of our fundamental moral principles. They should not be given awards, honors, or platforms which would suggest support for their actions” -- he is right. For you to paint it as anything other than right, is misleading at best and a lie at worst. In any event, you are wrong, sir.
"The Newman Society is linked to two organizations -- CatholicVote.org and the Fidelis Center -- whose programs are clearly geared toward bringing Catholics into the Republican Party."
That is simply not true. It's more of a "if the shoe fits" scenario, but they are not part of the republican party -- come on!
Bottom line is this; according to official Church teaching, it is wrong for Obama to speak at any Catholic University, based on his blatant opposition to Church doctrine, but you, and those like you, would rather ignore that fact and bash orthodox Catholics and Republicans instead.
Obama and Notre Dame - Los Angeles Times: "Obama and Notre Dame
Some Catholic groups are pushing to have the university withdraw its invitation for him to be commencement speaker."
Yes, they would be right-thinking Catholics -- that's all.