Three decades ago, Rob Portman began work as a young staffer in the White House of George H.W. Bush. Since then he has spent the bulk of his time in public service — and in Washington. Last week he announced that he would not seek reelection to the Senate in 2022. The rewards of public service, he said, “have been diminished for me. . . . It’s harder to get things done.”

Portman was not built for these political times. The Republican Party of Presidents George H.W. Bush and George W. Bush — in whose White House Portman also served — is now the party of Donald Trump, one in which its base is still enthralled with the 45th president and one that is infected with the toxicity of the radicalized QAnon movement and purveyors of disinformation, such as newly elected Rep. Marjorie Taylor Greene (R-Ga.).

Capitol Hill has long been gridlocked along partisan lines, but the climate has taken a dark turn in the aftermath of the storming of the symbol of American democracy by a ­Trump-inspired mob on Jan. 6. Beyond long-standing ideological differences, there are now personal antagonisms, concerns about safety and security, and fears. House Speaker Nancy Pelosi (D-Calif.) said Thursday: “The enemy is within the House of Representatives.”

This is the Washington from which Portman has decided to walk away. As he put it: “There seems to be less reward for figuring out how to be one of those people that says, ‘How do you find that sweet spot, that common ground, to be able to make progress?’ ”

But in retiring from office, he is also stepping away from the front lines in the battle to shape the future of his broken party, leaving others to deal with the crisis.

Portman began his Washington career at a law firm in the mid-1980s. He served for two years in the first Bush White House before returning to his hometown of Cincinnati. When a House seat opened up in 1993, he ran in a special election and won. He spent a dozen years in the House, a serious and studious legislator.

The second Bush to serve as president tapped Portman to become U.S. trade representative and later director of the Office of Management and Budget. Portman returned home to Ohio before Bush left office. When fellow Republican George Voinovich, a no-nonsense politician, announced he would not seek reelection to the Senate in 2010, Portman ran for that seat and won. He was reelected in 2016, defeating former Democratic governor Ted Strickland by 21 points when Trump was winning the state by eight points.

Portman has long focused on tax, trade and budgetary issues, and more recently on such problems as the opioid crisis that devastated his and other states. During the past four years, he kept his head down, avoiding drawing the ire of a vengeful president, rather than standing up and calling out the president as the times often demanded.

President Trump left a legacy of disillusionment and despondency across federal agencies. The Post's Lisa Rein and Tom Hamburger analyze Trump's lasting impact (The Washington Post)

He tried to concentrate on day-to-day legislating at a time of crisis for the country. Portman believes that was the right course for him and said he was able to make progress on issues of importance. “I was pleased that [Trump] signed 82 of my bills into law and it was important to have a relationship with the administration in order to do that,” he said. “I couldn’t have had 82 bills signed into law if I didn’t have a relationship. But yeah, I was put on the spot more than I would have liked.”

That is a mild way to describe the cost of maintaining a relationship with Trump. When Portman differed with the president, he chose not to make waves.

“I think there’s 50 instances where I disagreed with the president and I said so, but I tried to say so respectfully,” he said. “If you look at my Twitter account . . . there’s not a single partisan attack in there. I tried to stay away from, you know, following suit with the president’s approach.”

To some people, including some Republicans, Portman proved a major disappointment for not showing more backbone and speaking out forcefully against a president who trampled norms and threatened institutions.

Unlike Sen. Mitt Romney (R-Utah), Portman chose not to vote to convict Trump in the first impeachment trial a year ago. “While I don’t condone this behavior,” he said at the time, “these actions do not rise to the level of removing President Trump from office and taking him off the ballot in a presidential election season that’s already well underway.”

Like other senators, Portman will soon get a second chance to cast a vote to convict Trump. He has said that what the president did on Jan. 6 was “inexcusable” but has not tipped his hand on the upcoming trial. He continues to have questions about the constitutionality of a trial for a president no longer in office. “I want to be sure that we’re focused on what’s best for the country and helping the country heal,” he said.

Portman dissents from the analysis that describes the root cause of the paralysis on Capitol Hill as largely due to Republican obstruction, what some political scientists have called asymmetrical polarization, though, among other things, he went along with the decision never to allow a vote on the nomination of Merrick Garland to the Supreme Court and in the fall voted to confirm Amy Coney Barrett as voting in the general election was already in full force. Norman Ornstein of the American Enterprise Institute wrote that Portman “often opted for partisan strategy over actual lawmaking.”

Portman contends Barack Obama did not try hard enough to work with Republicans — a view sharply disputed by the former president in his recently published memoir. He calls Senate Majority Leader Charles E. Schumer (D-N.Y.) “extremely partisan,” while adding, “I’m not saying Republicans weren’t also engaged in that partisanship. And, you know, we all can recall that famous quote (from now Senate Minority Leader Mitch McConnell of Kentucky) that our job is to stop [Obama] from being successful.”

He added, “But that’s not what’s going on right now as we talk.”

At this moment, Portman said, he is concerned that President Biden will push ahead with his $1.9 trillion coronavirus recovery package on a partisan basis. “It’s very apparent to me right now that we’re going into a consequential month or two here where the Biden administration is going to have to decide, you know, are they going to follow Chuck Schumer down this partisan rabbit hole . . . and poison the well for the entire presidency,” he said, apologizing for mixing his metaphors.

Portman, who was part of the bipartisan group of senators who helped construct the $900 billion economic package passed late last year, has made clear to administration officials his concerns about the Biden plan. He praised Biden’s inauguration speech and the call for unity but said the relief bill is “totally out of touch with where Congress is in terms of Republicans and moderate Democrats.”

White House officials have said consultations with lawmakers are ongoing, but many Democrats are calling for Biden to use the budgetary tool of reconciliation to pass the measure on a simple majority vote. Biden said Friday that he prefers to pass the bill with Republican support but added that it “has to pass. There’s no ifs, ands or buts.”

As Portman prepares to leave government in two years, a political fire is burning in the country. His party is deeply divided, with members at war with one another. Partisan divisions are as deep as ever. Trump remains a divisive figure. The Department of Homeland Security warns about continuing threats of domestic violence “fueled by false narratives” and propagated by people unhappy with the outcome of the election.

Portman said Republicans must reject efforts to “move to the extremes” and unite around traditional conservative policies that defined the party when he first came to Washington. The way out of the political morass, he said, “is to find a reward for finding middle ground.” That is an elusive goal at best and one he was unable to achieve near the end of his career. On that, the lawmaker who made a career of trying to find consensus is leaving empty-handed. “I don’t know how that happens exactly,” he said.