Senator Lisa Murkowski, Republican of Alaska, on Tuesday cast the deciding vote for President Trump’s sprawling bill to slash taxes and social safety net programs, embracing a measure she acknowledged would harm Americans after securing carve outs to protect her constituents from its harshest impacts.

“Do I like this bill? No,” Ms. Murkowski, who appeared to be quietly seething as she was questioned about her vote, told NBC News. “But I tried to take care of Alaska’s interests. But I know that in many parts of the country, there are Americans that are not going to be advantaged by this bill.”

For weeks, Ms. Murkowski, the moderate fourth-term senator who has criticized Mr. Trump and has long been a swing vote in her party, had expressed concerns about the cuts to Medicaid and SNAP food assistance contained in the bill. It would impose strict new work requirements for both programs and reduce the federal contribution to their costs.

But with Mr. Trump demanding quick action and Republicans facing a tight vote margin in the Senate, Ms. Murkowski wielded unique leverage with party leaders to insist on changes. Republicans stuffed the bill with all sorts of goodies designed to win her over, including a provision that would allow certain Alaskan whaling captains to deduct more of their expenses.

Some viewed the backroom dealing as the work of a savvy and experienced lawmaker fighting for her constituents. But critics castigated Ms. Murkowski, saying she had besmirched herself by taking a bribe from Republican leaders to secure her vote for a bill that she, herself, said was dangerous for the vast majority of the country.

“Republicans are working Sen. Murkowski to create whatever Kodiak Kickback she needs to vote for this dangerous bill,” Senator Ruben Gallego, Democrat of Arizona, wrote on social media.

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