Editor’s note: Jeff Lawson is the CEO of Twilio.

People have wondered how an Internet without net neutrality would work. Net neutrality is more than just a debate, it’s not a hypothetical, and it’s real and alive today with SMS.

It is currently hypothetical that on an Internet without net neutrality, companies would need to “pay to play” and live by arbitrary, ISP-devised rules for accessing consumers who want and pay for their services. This is the so-called “fast lane.” While ISPs argue this is about network utilization and bandwidth costs, businesses worry that it’s far beyond that.

At stake is access to consumers, and ISPs monetizing their subscriber bases instead of providing the open pipe consumers pay for. While some companies think it’s just a problem for Netflix or other high-bandwidth applications like streaming video, it’s not. The very real potential is that if you don’t have the right relationships, abide by arbitrary rules or pay appropriately, your company doesn’t get slow access – it gets no access. We know because this is how SMS in the U.S. works today.

To understand neutrality, you have to understand an esoteric concept called “common carriage.” Since 1934 and the advent of common carriage in the U.S., telephone service providers have been prohibited from deciding who you can call or what you’re allowed to say while you’re talking. We take this freedom for granted in our voice communications. But for SMS, where messages aren’t afforded common carriage, carriers are responsible for policing the content of the communications.

Since 2010, innovators have used the power of communications by leveraging open access to SMS to deliver new products and services to consumers. In that time, companies such as Uber, Lyft, Airbnb, Nordstrom and The Home Depot have delivered customer experiences via the ubiquitous mobile medium of SMS.

But unfortunately — due to the lack of network neutrality rules — we’ve seen carriers block messages from customers for arbitrary and unpredictable reasons – for example, because they contain web links, because they reference alcohol, and because — and I’m not making this up — they reference content from Urban Dictionary. Do we really want an Internet where carriers police the content that we see? Should we really choose between a Fox News Internet and an MSNBC Internet?

Imagine if voice calls operated this way and your carrier could decide if you could receive a call from your bank, your grandma or your doctor based on whether they’re on some carrier-approved list. Seriously, imagine that. Zero people, probably even the carriers themselves, would support that plan. Yet it is exactly what happens with SMS, and it’s assumed that’s just how it is. This situation exists because SMS is not afforded common carriage protection like voice is.

Without net neutrality, service providers take on the obligation to police those who use the networks, how they use it, and what messages the network carries. This responsibility causes challenges, unusual incentives and, ultimately, instability for an ecosystem of innovation. This is what we’ve observed in the medium that currently lacks a mandate of neutrality — SMS.

Some innovations are very successful, others less so. But regardless of outcome, the key enabler is the ability to experiment with what innovation consumers want, and to do so on a predictably level playing field. The basic assumption is that innovators can, in fact, reliably and without interference reach the consumers they serve. It’s that spirit of innovation that’s spawned so much economic value in this country.

To the carriers’ credit, they’ve worked with the SMS ecosystem of innovation over the past several years to develop more sensible policies as the basis of a predictable foundation. However, it takes a substantial commitment to get it right. The thing is, the Internet already works right.

But even if access is granted to communicate with consumers on a carrier network, there’s still the “fast lane” issue. Carriers have recently proposed adding new fees for certain innovators to access customers via SMS while not charging those same fees to other operators. If this holds, companies like Google Voice, Skype and Twilio, as well as companies that use those services, would pay a carrier tax, while the incumbents enjoy preferential access to the network despite the fact that end subscribers pay for their service either way.

Those fees can make or break a business that relies on communications with their customers. And because carriers operate a monopoly on accessing their subscriber base, they could charge whatever they want. Sound familiar? This is the proposed system for web and mobile applications without net neutrality.

Phone calls have enjoyed common carriage since the Telecommunications Act of 1934, and it’s been a pretty good deal for consumers, businesses and access providers alike. However, the FCC has been reluctant to update its regulatory framework to account for all forms of communication — including technologies like SMS messaging and Internet traffic. But now is the time to change, as President Obama noted earlier this week by calling for Title II treatment — common carriage — for Internet communications.

Without net neutrality, the Internet as we know it will become arbitrary, unstable and hostile to innovation. We’ve seen what happens, and trust us, you do not want that Internet. Most importantly, consumer choice takes a major blow. Support an open Internet and net neutrality protected by common carriage as provided under Title II protection. This is an issue that impacts businesses and consumers alike. Make your voice heard and support a free and neutral Internet by contacting the FCC.