Washington (CNN) Chief Justice John Roberts will not vote to strike down Roe v. Wade and outright ban abortion. At least not yet.

The 64-year-old appointee of George W. Bush has never endorsed abortion rights or ever voted to invalidate a tough regulation. Earlier in his career, as a government lawyer, Roberts filed a brief at the high court asserting that the 1973 Roe had been wrongly decided and urged its reversal.

But in his new position as the deciding vote on abortion, Roberts today is moving cautiously on any narrowing -- or outright elimination -- of a woman's constitutional right to end a pregnancy. His stance is becoming more crucial as states race to pass laws directly challenging Roe. On Wednesday, Alabama Gov. Kay Ivey signed a near-total abortion ban.

Whether such laws are enforced in upcoming months and years likely rests with Roberts. And his 14-year record as chief justice and recent public signals, in the wake of Justice Brett Kavanaugh's replacement of Justice Anthony Kennedy, reveal two relevant traits for predicting the man in the center chair.

Roberts works incrementally, laying groundwork for his views, keeping an eye to upcoming cases, and avoiding any "jolt" to precedent, as he pledged at his 2005 Senate confirmation hearings.

He is also mightily concerned about the reputation of the Supreme Court and public regard for its legitimacy, and his own.

It is unlikely Roberts, who has pondered aloud what history will make of him, would want his legacy clinched by reversal of the 1973 landmark so drenched in the nation's politics.

Yet, that is not the end of the matter in the current charged climate over women's reproductive rights. Roberts could join his conservative brethren to reduce access to clinics that perform abortions and endorse other measures -- such as tighter regulation of physicians -- that diminish a women's ability to terminate a pregnancy.

If he takes that path, the 1973 Roe and cases since then that forbid government from imposing an "undue burden" on women seeking to abort a fetus before viability would not be outright overturned.

Still, Roberts would be breaking from Kennedy's pattern and disrupting life in America. In 2013, he readily turned away from entrenched Supreme Court legal reasoning as he took the lead for the conservatives to eviscerate a major part of the Voting Rights Act of 1965, in the case of Shelby County v. Holder.

Roberts' public message

Soon after the tumultuous Senate confirmation of Kavanaugh last October, Roberts pointedly differentiated the role of justices from that of elected officials.

"We speak for the Constitution," he declared in a speech in Minnesota. "Our role is clear. We are to interpret the laws and Constitution of the United States and ensure that the political branches act within them."

The following month, in response to President Donald Trump, Roberts asserted that federal jurists should not be identified in a political vein by the presidents who appointed them. "We do not have Obama judges or Trump judges, Bush judges or Clinton judges," Roberts said in a statement, asserting the independence of the judiciary.

But at the same time, Roberts often has reinforced the partisan divide at the Supreme Court, where the five conservative justices are appointees of Republican presidents, the four liberal justices of Democratic presidents. Accelerating the politics of the current moment, Trump campaigned against abortion rights in the 2016 presidential campaign and vowed to appoint justices who oppose Roe v. Wade.

Roberts has also voted to reverse four-decade-old precedents that have been part of the nation's legal fabric nearly as long as Roe v. Wade, in last June's controversy over labor union rights and this week's lower-profile test of states' immunity from lawsuits.

In this week's case, dissenting justices led by Stephen Breyer warned that the conservative majority was discarding a 1979 precedent without valid grounds and wondered what would be next. Breyer cited a 1992 abortion rights precedent, Casey v. Planned Parenthood of Southeastern Pennsylvania, which had upheld Roe, to support his defense of precedent but lightly also to highlight the potential stakes for reproductive rights.

"Today's decision can only cause one to wonder which cases the court will overrule next," Breyer wrote

Roberts' record on abortion

As a lawyer in the Ronald Reagan and then George H.W. Bush administration, Roberts criticized the legal underpinnings of Roe.

In 1990-1991 Supreme Court litigation over abortion counseling at family planning clinics that receive federal funds, Roberts urged the justices to use the case to reverse Roe. On behalf of the Bush administration, he wrote that the constitutional core of Roe, giving women a privacy right to choose whether to carry a pregnancy to term, finds "no support in the text, structure, or history of the Constitution." The Supreme Court ruled for the administration on the disputed regulation but declined to take up Roe as the Roberts' brief had urged.

During his Senate confirmation hearing in 2005, Roberts described Roe as settled precedent and said, "I do think that it is a jolt to the legal system when you overrule a precedent. Precedent plays an important role in promoting stability and evenhandedness." He said justices should not reverse a case simply because they believe it was wrongly decided.

Responding to specific queries from senators, he also said his Catholic faith would not be a factor in his rulings.

Since then, Roberts has sided in two major cases with states defending strict regulations, most recently in a 2016 Texas controversy. He dissented as the majority struck down the Texas measure that, among its provisions, required physicians who performed abortions to have "admitting privileges" at a local hospital. The law had caused the closure of several clinics.

Kennedy cast the key fifth vote, with the four liberal justices, to void the regulations in Whole Woman's Health v. Hellerstedt.

A potential shift?

Yet, last February, when the justices were faced with Louisiana's attempt to enforce similar "admitting privileges" rules, Roberts edged in a different direction.

A lower US appeals court had upheld the Louisiana law, rejecting the heart of the Whole Woman's Health decision. A Louisiana health clinic and physicians asked the justices to ensure that the new regulation not go into effect, and potentially shutter clinics, before a test of the law's constitutionality. They argued that the lower court had defied Supreme Court precedent from the 2016 case; Louisiana officials countered that their law could be distinguished from the Texas one struck down.

Without Kennedy and with all eyes awaiting the court's late-night action on February 7, Roberts joined with the four liberal justices to prevent the Louisiana law from being enforced while the clinic challengers filed their appeal on the merits.

It was a modest, incremental move whose meaning is not yet clear. Roberts could in the end approve the new physician rules when the merits of the dispute are heard.

But the action added another component to a chief justice who has assumed the role of the chief decider.