Syria's President Bashar al-Assad gestures as he takes questions from journalists after a meeting at the Elysee Palace in Paris in this December 9, 2010 file photo. REUTERS/Benoit Tessier/Files (FRANCE - Tags: POLITICS IMAGES OF THE DAY) (BENOIT TESSIER/REUTERS)

After Obama demanded Thursday morning that Assad step down in the wake of his crackdown on pro-democracy demonstrators, some of the president’s fiercest critics jumped aboard with their own calls for Assad’s removal.

That’s where the harmony ended.

Republican presidential candidates Mitt Romney and Rick Perry also used the occasion to chide Obama for not having called for the ouster sooner.

“America must show leadership on the world stage and work to move these developing nations toward modernity,” Romney said in a statement. “This means using the bullhorn of the presidency and not remaining silent for too long while voices of freedom and dissent are under attack.”

Perry said that the “Obama administration’s call for Syrian President Assad to step down is long overdue. President Assad has threatened the safety and security of not only the Syrian people but the surrounding world as well.”

The administration had said previously that Syria would be better off if Assad stepped aside, but Obama had resisted an explicit call for him to resign until Thursday. Officials also stressed that the administration enacted punitive sanctions on Syria, which it had not done on Egypt’s regime when it called for then-President Hosni Mubarak to resign.

Since the Syrian protests began in mid-March, the White House has ramped up pressure on Assad’s regime through statements and sanctions. By contrast, Obama called on Mubarak to resign within a week of the Egyptian uprising in late January.

Senior administration officials said Thursday that the White House was able to more quickly call for Mubarak’s resignation because Egypt had been a longtime ally and the administration could work with contacts within the regime to ensure a stable transition of power.

At least one Obama critic chose not to politicize the occasion.

House Majority Leader Eric Cantor (R-Va.), who was Obama’s chief antagonist in the debt ceiling fight, said in a statement: “The recent atrocities and Assad’s brutalization of his own people in Syria are extremely alarming and reflect a long history of anti-American hostility, and I join President Obama in calling for Mr. Assad’s resignation.”