Don't call it collusion between Democrats and Iran's mullahs, just call it an expectation in Iran of future flexibility in Washington, D.C.:
Five of the Democratic presidential hopefuls, including Bernie Sanders, Elizabeth Warren, and Kamala Harris, say that if elected they would revive the JCPOA—the Obama administration’s gravely flawed nuclear deal with Iran that gave Iran a nuclear sunset clause, allowed it to keep developing ballistic missiles and centrifuges, concocted a ridiculously inadequate inspection regime, and freed up billions of dollars for Iran’s subversion and terror. Another declared candidate, Joe Biden, has harshly criticized President Trump for leaving the deal.
The the awful 2015 Iran nuclear deal--which isn't even legally binding--pretends Iran didn't have a nuclear program--which they still have--and shields Iran from military attacks while they are pursuing nukes until the deal expires and removes the basis for international scrutiny of Iran's nuclear programs.
As I observed in a recent data dump:
The fact that Iran still hasn't abandoned the Iran nuclear deal despite Iranian complaints that America is essentially waging economic warfare on them speaks to how badly tilted the deal is to Iran, no?
So of course Iran likes the deal. And Iran would love to get Democrats in the White House who will listen to John Kerry, the worst secretary of state in living memory, and treat Iran like the future partner he knows the mullah-run country can be.
UPDATE: Another reason the mullahs pray for Democrats:
The U.S. Treasury Department is now weighing targeted sanctions that would curb the flow of less-visible [than existing oil sale sanctions] sources of the U.S.-denominated currency that Iran needs to pay for imports of basic goods—and to shore up its own flagging currency, U.S. officials said.
Without money, Iran can't make nearly as much trouble.