Steven Avery, the subject of the Netflix series "Making a Murderer." (Netflix)

Since the day he got into office, Wisconsin Gov. Scott Walker (R) has made pardons a hard no.

Even though the ability to restore rights to convicted criminals is one of the broadest powers that Walker — and almost every other governor — has, the second-term governor shunned the idea well before Netflix's "Making a Murderer" became a political sensation.

(CAUTION: Some mild spoilers ahead if you haven't seen the show.)

A petition to the White House requesting a pardon of Steven Avery, who is serving a life sentence for a 2007 murder conviction that his attorneys argue he was framed for, has reached 100,000 signatures — even though President Obama doesn't have the purview to pardon a state convict.

Walker does have the power to pardon Avery, but as MinnPost's Andy Mannix reports, he won't.

Since Walker came into office in 2011, he hasn't appointed anyone to a state advisory board to review pardons and has quietly shuttered the process altogether. Walker has never considered a single pardon from the thousands of applications.

He just doesn't seem interested.

"I just look at (granting pardons) and say that's not really why I ran for office," he told the Associated Press's Todd Richmond in 2013. "It's not what I campaigned on. It's not what I talked about."

The politics of pardons might help explain why Walker won't go there: There's simply no political incentive for Walker, who had presidential ambitions until he dropped out of the race, to grant a convicted criminal clemency, especially not one so high-profile as Avery. (Unless, of course, there is some definitive proof Avery didn't do what he's convicted of doing, which could change everything.)

Here are four big reasons why:

1. The risks outweigh the rewards

Simply put, clemency is a risky endeavor. Pardons — which restore to a criminal the power to vote, buy a gun and hold public office — are a governor's personal and political stamp of approval of said criminal.

It's kind of like putting yourself as a reference on a convicted criminals' résumé. That governor's name is often attached to that person for the rest of the pardoned person's life. Most notably, former Arkansas governor Mike Huckabee (R) faced scrutiny after lowering the sentence of felon Maurice Clemmons, who nine years later murdered four police officers in Washington.

In an interview with Alan Greenblatt of Governing Magazine, former Maryland governor Bob Ehrlich (R) called pardons a "political fear quotient" for executives.

That's why you so often see governors and presidents grant a whole bunch of pardons at the end of their time in office.

The high-profile nature of Avery's case makes it even less likely that Walker, or any other governor, would pardon him. There's that much more scrutiny on the governor's decision, the process — and what Avery, whose criminal troubles extend beyond this conviction and the 18 years he served for a wrongful rape conviction, does after that.

At the center of this Netflix original series is Steven Avery, a Wisconsin man who spent 18 years in prison for a violent sexual assault he didn't commit. Two years later, he was arrested for the murder of a young photographer named Teresa Halbach. (Netflix)
2. No one else is really doing it

Pardons have actually been on a downturn since the 1980s, dropping dramatically as America universally got tough on crime.

The governors of Walker's neighbor to the west, Minnesota, haven't granted a pardon or commuted a sentence in 25 years.

Governing Magazine's Greenblatt reports that's beginning to shift as the nation ends its war on drugs. Maryland Gov. Larry Hogan (R) and Illinois Gov. Bruce Rauner (R) both mentioned on the campaign trail in 2014 the importance of taking pardon power seriously.

But the focus of these new pardons tends to be on drug charges for nonviolent offenders, not convicted murderers like Avery. About two-thirds of the people President Obama has granted clemency to were in jail for drug charges -- 46 of whose sentences  he commuted in July.

But Obama isn't a big-time pardoner. The Washington Post's Katie Zezima reported as of 2014 he had granted the lowest number of pardons and commutations of any president since Dwight D. Eisenhower. His focus on commuting the sentences of non-violent drug offenders, though (which is different than pardons), has helped him surpass the combined number granted by presidents Ronald Reagan, George H.W. Bush, Bill Clinton and George W. Bush, according to The Post's Sari Horowitz and Juliet Eilperin.

3. There's no clear political battle line

The decision to avoid pardons is a bipartisan one.

As we mentioned, Obama doesn't appear to be a big fan of them. Former Massachusetts governor Deval Patrick (D) only pardoned four people and granted one commutation (a lessening of a prison sentence) on his way out the door. Former Illinois governor Rod Blagojevich (D), himself now in jail, left office in 2009 without pardoning anyone. (Although that backlog apparently encouraged his successors, Democrat Pat Quinn and Rauner, to make pardons a priority.)

New York Gov. Andrew Cuomo (D) had shied away from pardons for his past five years until recently, when in December he said he'd try to pardon thousands of nonviolent drug offenders who were convicted as teens.

For his part, Walker has faced criticism from Democrats and judicial advocates in his state for his unwillingness to even consider pardons.

Then-Senate Minority Leader Chris Larson (D) told the AP's Richmond in 2013 he thought Walker was shirking his executive duties and raising "questions about his commitment to a fair and just court system."

But critics of Walker's pardon policy haven't elevated their concerns to the level — and with the same passion — as critics of Walker collective bargaining policies did. (They forced a recall election, which Walker survived.) Labor and other hot-button issues just have much clearer battle lines than pardons.

4. It's a cultural thing

Each state and each governor approaches pardons differently. The AP's Richmond points out that Walker's predecessor, Democrat Jim Doyle, pardoned nearly 300 people during his eight years in office — much of it during his last few months — and was attacked by state Republicans afterward for abusing his pardon powers.

When Walker came into office, he told the AP's Richmond pardons just aren't something he believes in.

"To me, the only people who are seeking pardons are people who have been guilty of a crime and I have a hard time undermining the actions of a jury and of a court," he said.

And for Walker, that might be reason enough to avoid pardons altogether, especially one as high profile as Avery's. He doesn't have much to lose by avoiding them, but he has potentially a whole lot to lose if he wades into the drama.