A Tea Party group is frustrated that Republicans aren't doing more to capitalize on some recent bad news for Obamacare.

Responding to a Monday announcement by the insurer Aetna that it is withdrawing from most of the health insurance marketplaces, FreedomWorks said conservatives must pressure Republicans to make Obamacare "an issue in this election."

While Republicans spent the last three elections campaigning heavily on repealing the Affordable Care, they have said much less about President Obama's healthcare law this year. Yet the law has run up against some roadblocks this year, as major insurers have said they are withdrawing from the marketplaces, citing heavy losses.

FreedomWorks, which helped launch the Tea Party movement, said it's unfortunate that Republicans aren't making Obamacare a centerpiece of the election this time around.

"Aetna's withdrawal from nearly a dozen exchanges is another sign that Obamacare is unsustainable," the group said. "Premiums are rising as a result of diminished competition and unbalanced risk pools that have led to a higher than expected utilization of healthcare. Unfortunately, absent from the national policy discussion are the failures of Obamacare."