West Virginia Sen. Joe Manchin has ended any suspense about whether he would support, in any form, the Biden Democrats’ Build Back Better legislation. He dropped the hammer in an interview on Fox News this Sunday before Christmas.

The curious thing is that anybody is surprised. In this era of highly partisan, polarized politics, there is a close relationship between how people vote for president and for members of Congress and how they respond to specific issues. President Joe Biden won 51% of the popular vote in November 2020, but his average job approval is at 44% in the latest polling, with 50% disapproving. So if you discount Biden’s 2020 percentages by a couple of points, you get an idea of where he, his party, and BBB, their flagship issue, stand in each state.

Currently, only six of 100 U.S. senators represent a state that voted for the presidential candidate of the other party in 2020. Three of those are Republicans. One is Susan Collins of Maine, which Biden carried with 53% of the vote. But Collins was reelected the same day despite being outspent by a 9-point margin. The other two Republicans in Biden states are Pat Toomey of Pennsylvania, who is not running for reelection, and Ron Johnson of Wisconsin, who has not announced whether he’s running again. Biden carried their states with 505 and 49% of the vote, whereas Hillary Clinton lost both with just 47% and 46%, respectively.

There are three Democratic senators in Trump states. Sherrod Brown has managed to win in 2006, 2012, and 2018 as a pro-labor union leader populist in Ohio (45% Biden, 43% Clinton). Jon Tester has managed to win in 2006, 2012, and 2018 as a rough-hewn rancher who lost fingers in a tractor accident in Montana (41% Biden, 35% Clinton). Both are conviction politicians who have taken some political risk over the years and have managed to win nevertheless.

Joe Manchin is in a different position. West Virginia gave only 30% of its vote to Joe Biden and only 26% to Hillary Clinton. Discount the Biden percentage a bit, and you have three-quarters of the voters opposing BBB. And over his years as governor and senator, Manchin has not cultivated left-wing positions on economic and fiscal issues like Sherrod Brown or voted lockstep with other Democrats like Jon Tester has.

Oh, and by the way, Manchin was reelected by only a 4-point margin in 2018, down from his 61% to 36% win in 2012. He has repeatedly stated that he doesn’t like the high level of spending in BBB, doesn’t like the way Senate Democrats have gamed the CBO cost scoring in BBB, and opposes important specifics of BBB programs.

Senate Democratic leaders are used to a good deal of unity and cohesiveness in their caucus — more than Senate Republicans, or so I’ve observed over the decades. So maybe Majority Leader Charles Schumer and Majority Whip Richard Durbin just assumed that Manchin would come around on BBB. Or maybe Schumer is worried about the possibility that someone like Alexandria Ocasio-Cortez will run against him in the 2022 Democratic primary in New York.

What’s mysterious is why they ever thought Manchin would come around on BBB. Because of some special relationship with Joe Biden? Not likely: Biden was no longer a member of the Senate when Manchin was first elected in 2010. My own suspicion is that Senate Democrats and their leaders were lulled into complacency by press coverage, the subtext of which was that the BBB bill was great stuff, loved by the public, essential to overcoming the pandemic.

But the policy weaknesses of large parts of BBB have become obvious. The bill is underwater in the polls (unless you take particular components and phrase them as attractively as possible), and the extra spending seems more likely to fuel inflation than to reduce unemployment.

Why didn’t Joe Biden employ a bipartisan legislative strategy the way George W. Bush did in 2001, when his party had almost exactly the same congressional majorities (51-50 in the Senate, 221-214 in the House)? Bush pushed successfully for a tax cut that had significant support from multiple Democratic senators and for an education bill that was shepherded through the House by John Boehner and the Senate by Edward Kennedy. Biden decided to seek Democratic votes only, and so it turned out that his major proposal could be defeated by just one dissent. Very predictable.