During his six years as governor, Sen. Joe Manchin developed a rough three-part test he's taken to Washington: Are proposed programs paid for? Do they have bipartisan support? And do they solve a specific problem facing his constituents?

Why it matters: The West Virginia Democrat wields unparalleled power in a 50-50 Senate, but in many ways he still thinks of himself as a state executive with a practical streak — and that may spell trouble for President’s Biden’s $2 trillion social spending plan as it moves to consideration in the Senate.

• Those survival instincts, honed in a culturally conservative state, put him at odds with the major elements of Biden’s Build Back Better agenda.
• Manchin's focus on the bottom line — coupled with his instincts for what it takes to remain politically viable in a state President Trump won by 39 points — all but guarantee he'll trim the president's spending ambitions, people familiar with the matter tell Axios.

Manchin, 74, stands 6-foot-3 with a commanding presence. Married since 1967, he is a father of three; his son, Joe Manchin IV, carries on the family name.

• Manchin served in both West Virginia's House and Senate before being elected secretary of state and then serving as governor from 2005 to 2010. He's since served in the U.S. Senate.
• Manchin earned $491,000 last year from his stake in Enersystems, Inc., a coal brokerage business he founded.
• His daughter Heather is a pharmaceutical executive. His and her work have fueled critics who suggest they're compromised by their energy and biotech connections.

Manchin stands to play an outsize role as the split-control Senate debates the BBB plan. He hasn't shied away from threatening to delay or block it despite Biden being a fellow Democrat. And Democrats can't afford to lose even one vote so long as Republicans stay unified against it.

• Manchin has told colleagues he thinks extending the expanded child tax credit is too expensive; he’s also uncertain if middle-class families actually need it.
• For a new entitlement program like paid family leave, he has a strong preference for a compromise that could garner Republican support.
• On $550 billion in clean-energy tax incentives, the coal-state politician is unconvinced they'll accelerate the changes in the fossil-fuel industry that are already happening.

Between the lines: Manchin may end up supporting a package in the $1.75 trillion range this year, Axios is told, but he’s more inclined to wait and watch how inflation plays out at home and across the country.

• Given the number of differences he has with the House version of the bill, he sees 2022 as a much more likely timeframe, the people familiar with his thinking say.
• His acid statement Monday on Biden’s decision to tap the strategic petroleum reserve — calling in a “an important policy Band-Aid” — was filled with long-simmering frustrations, and indicates he's far from a final deal.
• “Historic inflation taxes and the lack of a comprehensive all-of-the-above energy policy pose a clear and present threat to American's economic and energy security that can no longer be ignored,” he said.

The big picture: Manchin, like Sen. Kyrsten Sinema (D-Ariz.), has earned the enmity of Democratic activists.

• They've kayaked to his luxury houseboat (“Almost Heaven”) and surrounded his Maserati Levante to demand he adopt more progressive positions, especially on climate change.
• Manchin shows little sign of backing down, however. High-profile fights with progressives help burnish his centrist credentials in West Virginia, where 74% of voters want him to oppose Biden’s plan, according to a recent survey.
• He also has an overall job approval rating of 60%, compared with Biden’s 32%.