The Republican from Kentucky told CNN's Michael Smerconish that without "a vote in Congress," Trump's missile strikes in Syria were an "inappropriate way to start a war."
"I think this is a wrong-handed notion that we just skipped the most important step," he said.
As for whether the 2001 Authorization for Use of Military Force, or AUMF
, could be invoked in the case of Syria, Paul said that those who might make that argument "are not intellectually serious people."
"That resolution specifically says Sept. 11... and if someone is gonna come on television or in any public forum and say Assad had something to do with 9/11, they're frankly just a dishonest person," he said.
"I mean, the generation of 9/11 certainly shouldn't bind us to a forever war in the Middle East. I think it's absurd," Paul added.
Asked by Smerconish if the images of children killed by Tuesday's chemical attack
didn't provide the same rationale for war as did images of Auschwitz in WWII, Paul replied that while he was "emotionally swayed" by them, there were "atrocities throughout the world" occurring every day.
"We have to decide when we are going to intervene as a country, when we are going to put our young men and women, put their lives on the line. And we don't, frankly, do it for every atrocity in the world," he argued.
"It doesn't mean we don't have great sympathy, but we have to debate when and where we go to war. That's what our founding fathers asked us to do," he added.
Paul also suggested the complex situation in Syria makes it different from the Nazi concentration camps of WWII, when "it was pretty clear" there was "one bad guy."
In Syria, he told Smerconish, "there can be an endless supply of enemies."
"You have to ask yourself: who takes over next? Are they better than the current occupant? So are the radical Islamic rebels -- the radical Islamic rebels in Syria -- better than Assad? There are also two million Christians ... in Syria, being protected by Assad, and they fear the Islamic rebels taking over. So there's a complicated decision-making process as to who are the good guys in the war," Paul emphasized.
As for President Trump's own admission that he had been prompted into action by images of dying Syrian children
, Paul said he did not agree.
"As horrific as those attacks were, and as heart-rending as the pictures and the atrocity and the children dying are, I don't believe that there was a national security interest of the United States," he argued.