Can Law & Order: Special Victims Unit overrule fans’ objections about its newest ADA?

The first season of Law & Order: Special Victims Unit made clear the emotional toll that investigating these “heinous crimes” takes on the dedicated detectives of the squad. And in the 18 years since, we’ve watched almost a dozen cops come and go, most of them walking away from the job, but on occasion falling in the line of duty. Things haven’t been much easier on the other side of the ampersand—the long-running procedural, now in its 19th season, has burned through assistant district attorneys at almost the same clip. In 2011 alone, three new characters—and one returning—assumed the responsibility of prosecuting sex crimes opposite SVU mainstay Olivia Benson, the detective turned lieutenant played by Mariska Hargitay.

When “Chasing Demons” airs Wednesday night, SVU will formally add ADA Peter Stone (Philip Winchester) to the crime-fighting lineup just weeks after he helped dethrone fan favorite Rafael Barba (Raúl Esparza). The son of the late Ben Stone (Law & Order’s Michael Moriarty) made more enemies than friends in his debut episode. At Jack McCoy’s (Sam Waterston) behest, he prosecuted Barba for a mercy killing. Ultimately, it was Barba’s decision to resign from his post, just as it was Esparza who chose to move on after six seasons. But Stone the younger isn’t the only one with his work cut out for him—Winchester failed to make a convincing case for the now-defunct Chicago Justice. It wasn’t entirely his fault, though; the procedural was billed as part of Dick Wolf’s Chicago empire, but was drowned out by echoes of the mega-producer’s other franchise.

Stone (and by extension, Winchester) is now set to make his third impression on viewers, many of whom are still smarting over the latest departure. It was an especially rough exit because Barba’s tenure was one of the longest—he’s second only to Casey Novak (Diane Neal), who held the position from 2003 to 2008 and recurred in later seasons. They actually have quite a bit in common: Both Novak and Barba were by-the-book prosecutors who grew disillusioned by perceived inadequacies of the law. The season nine finale saw Novak censured (or suspended), but she eventually returned in season 13 to trade off episodes with her predecessor, Alexandra Cabot (Stephanie March).

Like Barba, it was hard to imagine SVU without Casey Novak, who first strutted onto the crime scene in 2003’s “Serendipity,” immediately rubbing Benson and Elliott Stabler (Christopher Meloni) the wrong way. But the SVU cops and their full-time ADA (of which the show has only had four, with nine temporary ones) established mutual trust over time and Neal won over viewers. Yet she initially suffered from comparisons to March, who played Cabot for three seasons and one spin-off of SVU, proving nothing earns real devotion like a faked death. As Novak and even Barba prove, we’ve been through these deliberations before.

The SVU courthouse has had something of a revolving door for assistant district attorneys. A couple, like Kim Greylek (Michaela McManus) and Gillian Hardwicke (Melissa Sagemiller), hung around for an entire season, but most left after just a handful of episodes. The briefest stint was held by Mikka Von (Paula Patton), the Chicago lawyer who was fired by proxy over some extralegal stalling tactics. Patton had to be written off the show because she’d been cast in Mission: Impossible—Ghost Protocol, but that doesn’t take all the sting out of being dumped by Capt. Cragen (Dann Florek). Here’s his kiss-off, verbatim: “Yeah, well, nice knowing you. Pack your bags and go back to Chicago.” (Note: Cragen doesn’t even work for the DA’s office. That’s ice cold, Jack.)

SVU has a long history of these rocky introductions and departures; these speed bumps are even acknowledged in the storylines, which make frequent note of “cleaning house” or otherwise getting these rogue detectives to fall in line. And even when an old face returns, like Cabot did for “Turmoil,” that doesn’t mean the camaraderie remains intact. So Peter Stone is no worse off than Greylek or even his predecessor, Barba, who was himself tasked with restoring the SVU’s credibility after Stabler shot and killed the teenager who opened fired in the squad room. Similarly, Esparza was among the new cast members, along with Danny Pino and Kelli Marie Giddish, who had to bolster viewer confidence after Meloni departed.

More than anyone else, though, Hargitay has propped up SVU in its post-Meloni era. Benson’s long been the emotional center of the show, and she could find another complementary partner in Stone, who is also trying to come out from a parent’s long shadow. Stone also has the backing of McCoy, which has crossover potential written all over it, something that’s less of an issue now that Winchester’s character has been firmly planted in the L&O universe. Winchester still has an uphill battle, but the show could even benefit from the actor’s stoicism—his legacy lawyer’s poker face is the antithesis of Barba’s bared soul. And if it doesn’t work out, at least it’ll give the writers a chance to re-use that infamous “go back to Chicago” line.