White House senior adviser Dan Pfeiffer on Tuesday downplayed criticism over President Obama's decision not to speak at Gettysburg National Cemetery on the anniversary of President Lincoln's historic address there.

“It didnt [sic] work schedule-wise,” tweeted Pfeiffer in an online exchange with National Journal correspondent Ron Fournier.

Fournier pressed Pfeiffer, tweeting “Serious question: What is on his schedule that is more important than Gettysburg anniversary?”

Pfeiffer responded, by referencing the botched rollout of the Obamacare healthcare.gov website, tweeting, “Oh, I don't know, there's this whole website thing that someone suggested might destroy the Dem Party.”

Tuesday marks the 150th anniversary of Lincoln's Gettysburg Address, but the National Park Service announced weeks back that Obama would not participate in ceremonies marking the event.

Critics have questioned Obama’s decision not to attend, noting that past presidents have marked key anniversaries at Gettysburg.

White House press secretary Jay Carney on Monday gave no reason for the decision, but acknowledged the significance of the Civil War anniversary.

“I think that is an enormously significant event in our history, and I think Americans will take the appropriate time to consider it,consider the speech that was delivered there,” Carney told reporters. “But beyond that, I don’t have any updates on the President's schedule.”

Pressed on whether the president should have attended, Carney added “I think all Americans will share and marvel in the remembrance of that important date in our history and in the marvel that is that address.”

The anniversary also comes during a difficult stretch for the White House, as the administration struggles to fix problems with the website registering consumers in Obamacare’s new insurance exchanges. Obama has also been on the defensive over his broken promise that consumers could keep their current health plans even under the new law.

Polls show the health care woes have hurt Obama, with the president registering his lowest approval numbers.

On Tuesday, President Obama is slated to brief top senators on nuclear talks with Iran and then to speak at the Wall Street Journal CEO Council.

In the afternoon, he is also scheduled to meet with Defense Secretary Chuck Hagel.