As the Obama administration considers striking the Syrian regime as soon as Thursday, President Obama and Joint Chiefs Chairman Gen. Martin Dempsey are coming under increased criticism for their handling of the ballooning crisis.

Administration officials have told various news outlets that Obama is considering limited cruise-missile or bomber strikes against regime targets, likely for a period of three days. The strikes would be a punishment and deterrent aimed at Syrian President Bashar al-Assad in response to his reported use of chemical weapons against civilians near Damascus on August 21. Opposition sources have said they were told by “Western powers” that strikes could begin within the next few days.

In an interview during a diplomatic trip to South Korea, Sen. John McCain—one of the administration’s fiercest critics on Syria policy—said that recent statements by Dempsey signaled to Assad that he could escalate his use of chemical weapons against his own population without significant international consequences.

“General Dempsey has to be embarrassed,” McCain said about Dempsey’s letter to House Foreign Affairs Committee ranking Democrat Elliott Engel (D–New York) on August 19, in which Dempsey said the U.S. should not intervene militarily in Syria and that even destroying Assad’s air force was not a good idea.

“It would not be militarily decisive, but it would commit us decisively to the conflict,” wrote Dempsey, the highest-ranking military officer in the U.S. “Syria today is not about choosing between two sides but rather about choosing one among many sides ... We should evaluate the effectiveness of limited military options in this context.”

McCain said those comments, combined with Obama’s tepid responses to multiple other reported instances of chemical weapons being used in Syria by the Assad regime, convinced Assad that he could escalate his use of weapons of mass destruction.

“Dempsey made an incredible illogical statement and then a few days later we saw a massive use of chemical weapons,” McCain said. “I’m sure that Bashar al-Assad paid attention to the top military man in America’s words that we were not going to get involved.”

Obama also shares blame for giving Assad the impression he could escalate the use of chemical weapons by not responding forcefully to previous alleged chemical-weapons attacks over the past year, McCain said.

“Assad was able to use chemical weapons before and there was no response, and so why not do it again? This should surprise no one,” McCain said. “They viewed that not as a red line but as a green light, and they acted accordingly.”

In April, U.S. intelligence agencies reported “with varying degrees of confidence” that Syria had used chemical weapons against its political opponents on a “small scale.” Before that, on, August 20, 2012, Obama said at a news conference: “We have been very clear to the Assad regime, but also to other players on the ground, that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized. That would change my calculus. That would change my equation.”

For McCain and Dempsey, the war of words is not new. Last month, McCain threatened in open hearing to hold up Dempsey’s confirmation for a second term as Joint Chiefs chairman because Dempsey refused to publicly lay out military options for Syria.

Dempsey later sent McCain and Senate Armed Services Chairman Carl Levin (D–Michigan) a letter laying out several options and claiming that limited standoff strikes against the regime would require “hundreds of aircraft, ships, submarines, and other enablers” and “the costs would be in the billions.”

That letter is what prompted Engel, who has long called for arming the Syrian rebels, to ask Dempsey for clarification in a letter of his own arguing that limited standoff strikes could be conducted more easily.

“General Dempsey’s letter to Senator Levin seemed to reject a lot of the options for involvement for the United States in Syria,” Engel told The Daily Beast. “But you don’t have to jump in both feet; there are a lot of options in between.”

Engel said he still believes the Syria rebels should be armed, although it is a much more difficult proposition now that extremist groups have become more prevalent in Syria. He also said the U.S. response to Assad’s reported use of chemical weapons is not only about Syria, but about Iran and American credibility worldwide.

“Iran is closely watching what the United States does, because when we tell them we won’t allow them to have a nuclear weapon and all options are on the table, they look to see how we act,” said Engel. “I also think other rogue operations and terrorist groups are watching how we are acting to gauge how resolved we are.”

Engel acknowledged that the American public is war-weary, but said it is not in the U.S. interest to see Assad win the war or stay in power. McCain said that if Obama were to speak directly to the American people about U.S. involvement in Syria, that would go a long way.

But according to McCain, the limited strikes the administration is reportedly preparing for wouldn’t be a game changer in the Syria war—and wouldn’t succeed in deterring Assad from continuing to use chemical weapons.

“They might do a strike and say, ‘See we punished them,’ but it won’t change the equation. I would expect Assad to continue to use these weapons,” said McCain. “And other Assads around the world will now not hesitate to use these weapons and sooner or later they may be used against Americans.”