It's hard to imagine a state legislator thinking, "I want to put so many more people behind bars that we have to reopen an old prison to hold them all."

But this essentially what's happening in Nevada right now. The state is weighing 35 bills that would create new crimes or stiffen the penalties for existing ones.

"I think a majority, if not somewhere in the neighborhood of 75 to 80 percent of those bills, will make it out" of committee, Clark County deputy public defender Steve Yeager estimates. In fact, according to Yeager's office 19 bills, covering crimes from elder abuse to unlicensed horse betting, already have.

More criminal offenses likely means more prisoners — a step backward for Nevada, which was (like many states) working toward decreasing its incarceration rate through passing reforms to its criminal justice system. According to the Pew Charitable Trusts, Nevada's imprisonment rate decreased 5 percent between 2008 and 2013.

But that timespan obscures the fact that the prison population was higher in 2013 than it was in 2012 — and the state projects it's going to keep growing for the next several years. The state might have to reopen a prison it closed in 2008. This session is demonstrating how that sort of backslide can happen — and why other states should watch out.

How bills that imprison five people a year add up

It's easy to see why each individual bill has support. One bill that has passed out of committee would increase the statute of limitations for sexual assault to 20 years; it was introduced as a response to new allegations that have surfaced against comedian Bill Cosby. Other bills expand the list of drugs that are eligible for trafficking charges, or the definition of elder abuse. Even laws that might seem petty to some, like creating a felony for repeated graffiti offenses, can seem to be an important part of protecting public safety for others.

When you're looking at a single bill, it doesn't appear to cost the state much money — or any money at all.

"When these bills get introduced, someone will reach out to the Department of Corrections and say, 'Can you look at this bill and see what the financial impact would be on your agency?'" Yeager says. "And they'll almost always end up saying, 'Well, zero, because it's a negligible amount of folks, and that's not really going to have an impact.'"

But these bills, he says, add up. Yeager's office did the math in a memo, which they sent to the state assembly in late March — but have had to update as even more bills have had criminal penalties added to them. "If these 35 bills only affect five individuals per bill and the court sentences each individual to two years in prison, these 175 new prisoners will cost the State of Nevada $7,229,600" over the next two years, Yeager says. Take that number again for the five people who'll be incarcerated under each bill the next year, and the year after that, and you have a lot of money.

You also have another few hundred prisoners, who could make the difference between keeping the number of prisons Nevada has now and reopening the prison the state closed in 2008.

The problem with pursuing public safety at all costs

The public defender's office has argued that reducing incarceration is fiscally responsible — an argument that has been very persuasive in plenty of other Republican-led states, and which Yeager says have worked in Nevada in the past. But this year it seems to "fall on deaf ears."

Indeed, the chair of the state assembly's Judiciary Committee, Ira Hansen, has explicitly said (according to the Las Vegas Review-Journal) that the cost of incarceration doesn't matter to him if public safety is being served. "If in fact we do need to send someone to prison, then so be it," Hansen said.

But that still implies there's a conscious weighing of whether someone ought to be sent to prison, as opposed to alternative forms of punishment. And that's usually not how these debates work. Legislatures often tack civil or criminal penalties onto bills as a way of emphasizing that violating the law would be bad — not because they're actually arguing that everyone who breaks it needs to go to prison.

Take the graffiti bill, for example, which would send someone to prison the third time he or she is convicted for graffiti. Someone convicted of a misdemeanor for graffiti already gets penalized — in part with community service, which, Yeager says, often involves cleaning up graffiti. Does it make sense, he asks, to lock that person up for more graffiti — or assign her to help clean it up?

What's going on in Nevada right now is a warning to the rest of the states that have made strides in criminal justice reform. Actually moving beyond mass incarceration, and shrinking prison capacity for good, requires more than a few years of attentiveness. It requires thinking about the bigger picture when considering individual bills, even those with "negligible" impacts. And it requires taking public safety seriously but asking "Does someone need to go to prison for this?" whenever the legislature wants to make something a crime — and forcing the bill's supporters to explain why the answer should be yes.