On Wednesday night, the Washington Post published an explosive report detailing how Jeff Sessions, while a senator, had two meetings with Russian Ambassador Sergey Kislyak — and failed to disclose them when asked, under oath, about the Trump campaign’s ties to Russia.

A growing number of powerful Republican lawmakers spent Thursday calling for Sessions to recuse himself from the politically-explosive FBI investigation into the Trump campaign’s ties to Russia. Late Thursday afternoon, Sessions gave in, telling reporters that he would not participate in probes “related in any way to the campaigns for president of the United States.”

Sessions spent the rest of the press conference arguing, unconvincingly, that he hadn’t misled Congress when he denied meeting with the Russian envoy. But what makes the apparently friendly meetings so remarkable isn’t simply that they are now at the center of another Trump-Russia scandal. It’s that Sessions, for nearly 20 years, was considered among the most reliably hard-line of Russia hawks in the Senate.

That position began to change as the Alabama senator moved closer to candidate Donald Trump during the 2016 election cycle. By the time he was fully a member of the Trump team, Sessions had changed his messaging on Russia so notably that it became a point of reportorial interest, with USA Today noting that his “tough talk about the threat Russia poses to the U.S. and its allies in Europe” had “undergone some revisions.”

The news of Sessions’s meetings with the Russian ambassador raises serious ethical and legal question because it directly contradicted his own testimony in January during his Judiciary Committee confirmation hearings for attorney general.

But it also raises a set of broader and more explosive questions: What changed for Jeff Sessions when he entered Trump’s orbit that turned him from a Russia hawk into someone eager to do business with the Kremlin? And what does all this coziness between Trump administration surrogates and Moscow mean for US policy, the election, and the country?

Sessions used to warn that Putin wanted to put countries back under the “Soviet boot”

As a senator, Jeff Sessions was long known for tough talk on Russia and for advocating a strong missile defense system (in no small part because some of that industry is located in Alabama).

On the Senate floor in September 2008, Sessions detailed his thinking on the matter:

Russia's recent actions in Georgia remind us that country, which we once hoped was on a path to greater integration into the global world community, might again be seeking to restore old Soviet ideas of dominance throughout their neighbors and in Eastern Europe, all of which should serve as a motivation to move ahead with the necessary capabilities to defend ourselves and our allies from missile attack, in particular.

In the same speech, he complimented the Czech Republic and Poland for establishing missile shields against the “big neighbor to the East,” Russia. He then turned to Russian President Vladimir Putin, who had just threatened to take action against former Eastern bloc nations that planned to house NATO missile defense systems on their territory.

I would suggest something more is at stake here, and I think it is something that the Poles and the Czechs and the Georgians and the Ukrainians and the Estonians and the Latvians and the Lithuanians understand full well, and that is that Putin desires to reestablish hegemony over the former Soviet satellites. They think they have a right to tell Poland whether to undertake a military partnership with the United States. They have no right whatsoever to do so. Poland is glad to be rid of them. They are glad to be out from under the Soviet boot. They have no intention whatsoever of allowing themselves to fall back under their dominance. They have values that are close to our values. They want to be part of our heritage and the Western heritage.

Those weren’t just words. Sessions was a Russia hawk when it came to legislation as well.

Sessions’s public criticism of Putin shaped how he voted in the Senate

In 2010, the Alabama senator voted against the New START treaty reducing nuclear weapons, arguing it made the United States too vulnerable. He made it very clear he felt the Russians were given too much in the deal, and the United States not enough.

“The Russians did not win with missile defense,” he said during debates over the treaty. “They have already won and have attempted to codify it with this treaty.”

“I am deeply disappointed the Russians have been so intransigent, hardheaded about this treaty and other relations with the United States,” he said. “If they have nothing to hide, what is going on here? I am concerned about this.”

If anything, after that, Sessions’s position on Russia only turned more hawkish.

Sessions was notably strident in 2014 when he called for increased sanctions and Russia’s ouster from the G8 group of nations. Russia, he said publicly, should be made to “feel pain” over Putin’s aggressive movement into Ukraine and (then expected) military movement from Moscow into Crimea.

At the Brussels Forum in March 2015, a reporter from RealClearWorld asked Sessions what he expected from Putin in the future. The senator replied, bluntly, that “there’s a danger that they continue this overreach” by trying to dominate other Eastern European nations, including close US allies such as Estonia.

“It needs to be clear that Russia knows that there will be a high price to pay if this behavior continues,” he said.

That type of tough talk began to change abruptly in early 2016, when Sessions began to eye the Trump team.

Meet the new Jeff Sessions, fan of reaching out a hand to Putin

In March 2016, just after Sessions was named as a foreign policy adviser to the Trump campaign, his public position on Russia began to shift.

At a March 17, 2016, breakfast meeting, reported on by USA Today, Sessions said “an argument can be made there is no reason for the U.S. and Russia to be at this loggerheads.”

“Somehow, someway we ought to be able to break that logjam,” he said. “Putin may not be able to be dealt with, but I don’t condemn [Trump’s] instincts that we ought to attempt to do that.”

Four months later, in July 2016, CNN tried again to pin down Sessions on the matter of Russia and the Republican candidate.

Reporter Jim Acosta asked the senator about Trump’s jarring call for Russia to hack into the emails of then-Democratic candidate Hillary Clinton. Acosta said that “Democrats were “suggesting that perhaps [Trump is] taking a soft approach on Russia because he has business dealings there.”

The CNN host then asked Sessions about Trump’s investments and Russia ties. “What are you aware of? Is he coming clean on this?” Acosta asked.

Sessions at first dodged the question, pointing out that Clinton had “left her email system totally vulnerable to a Russian penetration.” He then, somewhat nonsensically, continued, saying he had people come up to him “all the time” to say “if you want to find out where those 30,000 emails are, why don't you ask the Russians? They're the ones that have them. So she has made a huge error in there.”

He went on to say that Russia and the US really needed to let bygones be bygones:

Secondly, this whole problem with Russia is really disastrous for America, for Russia and for the world. Donald Trump is right. We need to figure out a way to end this cycle of hostility that's putting this country at risk, costing us billions of dollars in defense, and creating hostilities.

Later in the interview, Acosta tried again. This time, he turned to the question of Putin himself. “Is Vladimir Putin a good leader or a bad leader?” he asked. “Is he a good man or a bad man, in your view?”

Sessions’s response was opaque:

We have a lot of bad leaders around the world that operate in ways we would never tolerate in the United States. But the question is can we have a more peaceful, effective relationship with Russia. Utilizing interests that are similar in a realistic way to make this world a safer place and get off this dangerous hostility with Russia. I think it's possible.

And with that, Sessions’s transformation from a vocal Russia hawk into a vocal supporter of closer cooperation with Putin was complete. That month, Sessions held the first of the two meetings with Kislyak that have triggered Trump’s latest Russia scandal and raised questions about whether Sessions will, or should, keep his job.

Watch: Sessions just added to Trump’s Russia problems