That's why Cheney repeated the Saddam/9-11 lie so often after it had been debunked by everybody in the known universe, including George Bush. He knew it would work for awhile.
And the fact that all of these arguments were lies didn't deter Cheney a bit. "Truth" was something to be sorted out by other people.
Splattering out new right-wing arguments on Iraq is essentially what Bill O'Reilly's was doing in his interview with Hillary Clinton:
. . . Clinton stumbles on Iran. Both she and Obama want out of Iraq, but the unintended consequence of that would be a much bolder Iran. Those fanatics will spin a U.S. withdrawal as an "Islamic" victory. And then, most geo-political experts agree, Iran would attempt to dominate Southern Iraq.
The old right-wing shibboleths on Iraq withdrawal used to be that the majority Shiites would commite genocide against the Sunni population or that al-Qaeda would take-over or that Iraq would become a base for attacks against the United States.
But these arguments aren't working anymore. So O'Reilly cooked up Iranian domination as an "issue" to be tossed at Hillary Clinton and Dick Morris liked the idea so much that he featured it in his own column.
The argument is that Iran would seek to "dominate" Iraq or at least the Southern Iraq area around Basra.
Hillary Clinton responded not unreasonably that the Iraqis would reject Iranian efforts to dominate on ethnic Arab v Persian grounds.
She could have given 10 or 12 other objections as well, the most relevant being that Iran doesn't have the resources needed to dominate Iraq or any part of Iraq.
Despite spending $600 billion over the last five years, the U. S. still does not "dominate" Iraq enough to count on the Iraqi government, armed forces, or police as allies. Consequently, the Iranians would have to spend more than our paltry $120 billion a year in order to achieve real "domination."
However, Iran's actual defense/military budget is 6.2 billion dollars per year. That's not only not enough to militarily or diplomatically dominate Iraq, it's barely more than half of the $12 billion U. S. military expenditures in Iraq for the month of April 2008.
In my thumbnail estimate, the Iranians have enough resources to occupy Iraq for about one week per year if they decided to invade. Otherwise, they're going to be stuck in the same boat the U.S. is in, trying to help the Iraqis stabilize by encouraging negotiations among the various Iraqi Shiite groups. If the Iranians are going to have leverage, they're going to gain it through the kind of diplomacy they exercised to broker the cease-fire in Basra.
Otherwise, they're not really a problem.