There's no one in the progressive movement (other than some MMT folks) that have a serious rebuttal (no...a refutation) to the conservative, deficit hawk, argument. Even Paul Krugman, who is quite prolific when it comes to challenging the conservative arguments on deficits, government spending, entitlements and such, will set himself up for destruction each and every time when says things like, "The debt is not a problem in the short term, but we need to get long-term structural deficits under control."
It is that "long-term" stuff that undermines his efforts.
Once progressives agree with conservatives that there IS a problem, never mind if it has to be addressed now or later, then conservatives just easily come back and say, well, if you agree there is a problem, then why don't we just fix it now and be done with it?
Until we get a progressive that understands our monetary system; that understands the FACT that we can't go broke and that deficits add to the financial balances of the public, and go on to become part of the inheritance (and wealth) of current and future generations, as opposed to being a burden...until that happens, we will lose every, single, time.