That sentence should prompt a few comments.
Ron Paul has never said Iran should be allowed to develop nuclear weapons without resistance.
What Ron Paul said was the USA should not be entangled in so many wars as the world’s policeman or empire.
Laying siege on Iran has an effect. Tripling the sanctions and enforcing others to abide them would lead to an overthrow of the Mullahs by the Iranian people because starvation is always a local issue.
But bombing by the USA or under cover of its NATO surrogate, or by the Israelis will only anger the Iranian people and entrench further the power of the psychotic terrorists that answer to the Mullahs.
Ron Paul would back a siege because it is simply a refusal to allow Iran to trade oil, to have visas to travel, to perform any international banking, gold, precious metals or any commodity transactions or anything of value that can be monetized. These sanctions do have an effect but are leaky for lack of enforcement.
Enforcement of an oil embargo could be carried out by placing a carrier group near the Strait of Hormuz with standing orders to shoot down or sink anything coming from or going to Iran. Such as action has no effect of making war on the ground. Ron Paul could sign for this.
The invasion of Iraq and Afghanistan allowed for the complete isolation of Iran as all countries bordering it are or were at one time in agreement with the West in regards to sanctions of Iran. Ron Paul would not sign for an invasion of countries to isolate Iran. I expect he would sign for placing sanctions on all three, Iraq, Afghanistan and Iran, but even laying siege to all three may have been unnecessary. Leaving Saddam Hussein in power would not have empowered Iran as Iraqis and Iranians ruling classes are permanent enemies of each other. Afghanistan is mostly influenced by Pakistan and there is no friendly basis for Afgans and Iranian governments to carry on against the sanctions of the West. Afghanistan is poor and would not be helpful to Iran even if its governing class chose to participate in evading sanctions.
Starve them, it’s the only way. I expect Ron Paul would be fine with that as it involves no aggressive military action.