The Popular Mobilization Forces (PMF) militias were arguably needed to hold off ISIL in 2014 when much of Iraq's corrupt armed forces in the north collapsed.
Unfortunately, Iran was too involved in organizing the militias. And now they are a threat to rather than saviors of Iraq:
Until the territorial defeat of ISIS, the Iraqi government needed the PMF and allowed their operational independence. Now, without a common enemy, these militias have no explicit purpose, yet most refuse to disband and relinquish control over areas they control. The future of these militias is unclear, and the Iraqi government needs to take control of them or risk losing authority to militia leaders who act as Iranian proxies and regional warlords with personal armies.
This sounds about right:
The Iraqi regime has a couple of options for how to deal with the militias operating within its borders now that collusion is no longer an effective strategy: integration, containment, or suppression.[1] All willing militias should be integrated into the Iraqi military following the example of the Peace Brigades. Those that do not cooperate tend to be militias that resemble criminal gangs and answer to Iran like Kata’ib Hezbullah, which has publicly rejected the decree. These groups should be contained, economically deprived, and shut down like the scrap metal militias operating in Nineveh. Because these militias are well funded and trained by Iran and the Iraqi military is comparatively weaker, they should not be violently suppressed especially because it could lead to escalation and war with Iran, which would be destructive to Iraq and its citizens. Iraqi forces should instead work to contain them.
I've written about the need to bring the militias under control or ultimately disband them. The weak Iraqi government has to be careful but the job must be started before the militias are as entrenched in Iraq as Hezbollah is in Lebanon.
UPDATE: And while a militia loyal to Sistani and reporting to the prime minister is better than a pro-Iran militia, it is still a bad thing to have.
Mind you, this is probably the last militia that would need to be disbanded.