Hillary Clinton is defending the use of the death penalty at the federal level, even as she criticized the capital punishment system at the state level.

The Democratic presidential candidate during a Sunday night town hall at Ohio State University said that while states have "proven themselves incapable of carrying out fair trials," a federal death penalty should remain in place for extreme cases.

Clinton said that "given the choices we face from terrorist activities primarily in our country that end up under federal jurisdiction, for very limited purposes, I think it can still be held in reserve for those."

Though Clinton backs a federal death penalty as a way of dealing with convicted terrorists, the numbers show that it's rarely used that way.

"[Clinton] made it seem, in her comments, as though the federal death row was filled with terrorists. In fact, out the 62 people, one of them is a terrorist," said David Menschel, a criminal defense attorney and criminal justice reform advocate.

Boston Marathon bomber Dzhokhar Tsarnaev is the lone inmate on federal death row for a terrorism conviction.

The rest of federal death row is filled with inmates convicted of the same crimes as those in the state systems, but whose crimes are distinguished by a federal tie-in that ranges from killing a state police officer to burying a murder victim's body on federally owned land.

"The people on federal death row are mostly indistinguishable from state death rows," Menschel said.

Boston Marathon Bomber Dzhokhar Tsarnaev is the lone inmate on federal death row for a terrorism conviction.

Even in terrorism cases against the state, the death penalty is inconsistently applied. Menschel said many of the defendants convicted of terrorism offenses at the federal level get life sentences rather than the death penalty -- including Ramzi Ahmed Yousef, who was convicted of the 1993 World Trade Center bombing that killed six and injured more than a thousand people.

In 2010, then-Attorney General Eric Holder, put the number of international and domestic terrorists in Bureau of Prison custody at more than 300.

Since the 1920s, the federal government has executed 37 people, according to the Death Penalty Information Center -- largely for murder, robbery and kidnapping.

Oklahoma City bomber Timothy McVeigh is the only federal prisoner since the 1950s to be executed after a terrorism conviction. McVeigh abandoned his appeals and was put to death just four years after his conviction.

8.Timothy McVeigh is the only person executed since the Julius & Ethel Rosenberg executions in 1953 who meets the @HillaryClinton definition — Rob Smith (@thisisrobsmith) March 14, 2016

In the presidential race, Clinton is the only candidate to have a stance only partially approving or disapproving of the death penalty. Her rival for the Democratic nomination, Sen. Bernie Sanders (I-Vt.), opposes the death penalty outright, while the four remaining Republican candidates all support the death penalty at the state and federal levels.

Menschel, who opposes the death penalty, said the stance gives Clinton room to pivot toward a more "tough on crime" stance in coming months, if need be. Criminal Justice Legal Foundation legal director Kent Scheidegger, who supports the death penalty, agrees.

"She’s straddling the fence, and it’s a barb-wired fence. I don’t think she wants to come out full-bore for [the death penalty] in the primaries and doesn’t want to come out full-bore against it in the general election," Scheidegger said.

Scheidegger noted that while he believes the death penalty is needed at the state level to both punish and deter, he's unsure of its value as a deterrent in terrorism cases -- "unless maybe for accomplices."

The former Secretary of State made her remarks in response to a question from Ricky Jackson, a man exonerated from death row after 39 years. Jackson told Clinton that he came "perilously close to my own execution" despite being innocent.