If Netflix has seemed a little slow to load on your laptop or smartphone in recent months, it's probably not your imagination. Average Netflix speed and quality in the U.S. was already pretty subpar, according to Netflix, at about two megabits per second (Mbps) — hey, that was better than Mexico and Ireland — but it's been dropping since last October:

And that drop isn't uniform across internet service providers (ISPs), as this chart from The Wall Street Journal shows. The slowdown has been particularly egregious for customers of Verizon, one of the country's largest ISPs due to its FiOS fiber-optic broadband service.

Nobody's really accusing Verizon of outright "throttling" Netflix service — that is, treating streaming movies differently from say, news articles once they're in the Verizon pipeline — but it appears Verizon has found other ways to slow down Netflix traffic without, technically, violating its stated commitment to net neutrality.

Verizon and other large ISPs are in a long-running dispute with Netflix over whether the movie-streaming powerhouse — the single largest user of internet bandwidth, followed by YouTube — should pay extra for its heavy usage, and how. Verizon wants to charge Netflix outright — a big reason it successfully sued the Federal Communications Commission to overturn its net-neutral Open Internet rules.

The traffic jam now is at the portals connecting Verizon's broadband networks — the ones that go into your house — and the long distance fiber optic networks that carry internet data long distances, according to The Wall Street Journal. Right now, Netflix sends a lot of its data through lines operated by Cogent Communications, and both Cogent and Netflix say Verizon is purposefully keeping some of its portals shut and delaying equipment upgrades to degrade Netflix streaming.

Verizon says it treats all internet traffic equally, but it also is vocally insisting that bandwidth hogs like Netflix pay for dumping so much data into its network. The existing "peering" agreements that govern the interchange of data from one network to another are premised on fairly equal reciprocity — that Verizon will unload about as much data onto Cogent's pipeline to Netflix as Netflix sends to Verizon, say.

With video streaming services, the traffic is heavy and mostly one-way. The slowdown in service started at about the same time Netflix started offering super-HD service to all its subscribers. Netflix has built up its own data-distribution network, but it doesn't want to pay Verizon and its fellow ISPs to hook up directly with their networks.

If you want more technical and legal details, The Wall Street Journal's Simon Constable talks with Shalini Ramachandran, one of the reporters who wrote The Journal's story on the Netflix-Verizon fight:

Constable also spoke with Cogent CEO Dave Schaeffer, who argues that Verizon, Comcast, and other ISPs restricting traffic at the network interchanges are violating their agreements with consumers to provide internet service at certain speeds:

So what if Verizon isn't your ISP? There's strong anecdotal evidence that Comcast, AT&T, and other ISPs are also somehow slowing Netflix service, either through sins of commission or omission. If you look at the chart above, you'll see that their Netflix performance has dropped since October, albeit at a less dramatic rate. Perhaps more damning is that Google Fiber's Netflix service is actually improving — and Google owns one of the largest network peering facilities in the world.

As MIT Technology Review's David Talbot notes, it's really hard to uncover why Netflix service is slowing down for so many users, since peering agreements and data on network interchanges don't have to be released publicly or reported to the FCC.

This may all seem pretty esoteric. After all, notes Sam Gustin at TIME, "most consumers don't care how Netflix videos arrive on their computer or TV — they just want the service to work." And like it or not, Gustin adds — or even understand them or not — "private peering deals are the new front in the war between the broadband giants and Internet content companies." Netflix viewers are just collateral damage.