Sometimes 50 senators can get more done than 60.

Thats one of the big takeaways from the enactment of the American Rescue Plan , the COVID-19 relief bill that Congress passed and President Joe Biden signed this week. It calls for $1.9 trillion in new outlays, which, amazingly, is exactly how much Democrats sought when they first sketched out their proposal in January.

The contents of the legislation didnt even change much. The law includes groundbreaking , previously controversial initiatives that will deliver direct cash payments , support child care providers and upgrade the Affordable Care Act for the first time in the programs existence. The only big concession Democrats made was dropping a proposed increase in the minimum wage though theyre still hoping to pass that separately later in the year.

The accomplishment is remarkable because it feels so different from what happened in 2009, when President Barack Obama and his Democratic allies took up an economic stimulus package and then health care legislation. Each time, party leaders made concessions and settled on less spending than they wanted, leaving them with a stimulus that wasnt big enough to produce a quick recovery and a health care law that still left some middle-class people with high insurance costs.

Although Biden and the Democrats repeatedly said they would not make the same mistakes this time, they also were operating at an apparent disadvantage because they had only 50 votes in the Senate rather than the 58 and eventually 60 that made up the Democratic majority of 2009 .

But the caucus in Obamas term was stacked with relatively conservative Democrats from Republican-leaning states who consistently acted as a brake on liberal ambitions. Nearly every one of those senators is now gone, leaving Democrats with a caucus that seems a lot more inclined to think big at least for now.

The End Of An Old Political Era

The Obama presidency came toward the end of a political transformation that had been underway since the 1970s, as white conservative voters stopped voting Democrat and started voting Republican. The effects were especially profound in the South and interior West, where voters increasingly backed GOP presidential candidates but were willing, sometimes, to let familiar Democrats in Congress keep their seats.

The Senate of 2009 had quite a few of these Democrats, including two from Arkansas, two from North Dakota and one each from Louisiana, Missouri and South Dakota. (There was also one conservative member of the caucus from a liberal state: Joe Lieberman, the independent senator from Connecticut.)

Although these conservative Democrats benefited from name recognition and other advantages associated with incumbency, most survived politically because they had relatively conservative political profiles that their constituents found acceptable. That meant rejecting anything that sounded like big government and avoiding close association with Democratic Party icons which, in 2009, included the newly elected and generally popular president.

There were a considerable number of congressional Democrats 12 years ago who didnt get elected because of the national party; they were elected almost in spite of the national party, Phil Schiliro, who was White House director of legislative affairs under Obama, told HuffPost. Its a lot harder to get consistent unity within the caucus because they are reflecting the views and political realities of their states. And having some independence can make the difference in whether they are able to stay in the House or Senate. Thats just the reality.

That reality came into play during the debate over the Obama stimulus proposal , which in the Senate had grown to more $900 billion in outlays still less than what some economists (correctly) believed the economy needed but more than what conservative Democrats wanted the government to spend. Working together with a handful of moderate Republicans, these conservative Democrats pushed to shrink the bill and eventually prevailed, leaving a program with expenditures of less than $800 billion.

The overall number was getting way too big to manage, Mark Begich, who was a Democratic senator from Alaska, told Michael Grunwald for his book The New New Deal. The goal was to get a lid on it. We said under 800, no more, we cannot go above that.

The same dynamic played out months later in negotiations over the health care bill . Top Democratic leaders wanted more spending and deeper cuts for health industry groups than conservative Democrats would accept. More liberal Democrats also wanted a public option, a government-run insurance program that would be open to some people as an alternative to private coverage. Conservative Democrats opposed that, too and prevailed yet again.

The marginal votes were always the conservatives, Jason Furman , a top Obama economic adviser who is now a Harvard University professor, told HuffPost. Because if you lost them, the bill would fail, and for the liberals, anything was better than nothing.

The Beginning Of A New Political Era

If the goal of these conservative Democrats was to hang on to their seats, it wasnt an especially successful gambit. Nearly every one of those Senate seats is now in the hands of a Republican because the Democrat retired or lost reelection in or after the 2010 midterm elections.

But just as Democrats over the last decade lost seats in states that have turned Republican, Republicans lost seats in states that have turned Democratic. That accounts for seven new seats in the Democratic caucus relative to 2009 two each in Arizona and Georgia , plus one each in Maine, New Hampshire and Nevada. Those gains are why the Democrats now have 50 seats, allowing them to govern as a majority because Vice President Kamala Harris can break a tie vote.

Although its the narrowest possible majority a party can have in the Senate, its also a lot more homogenous than its 2009 counterpart because there are so few conservatives from Republican-leaning states. For Democrats, that they have such a narrow margin these days is helped by the fact that many of the more centrist senators of years past... are no longer in the Senate, Jim Manley , who was a top aide to former Senate Majority Leader Harry Reid (D-Nev.), told HuffPost. The caucus as a whole is much more progressive than when I left in 2010 and much more unified.

The most conspicuous outlier to this pattern is Joe Manchin of West Virginia, who is the most conservative Democrat in the caucus. Not coincidentally, Manchin is also the only Democrat from a state that voted overwhelmingly for Donald Trump in the 2020 presidential election.

But in the COVID-19 relief debate, Manchin used his leverage to get concessions that, whatever their merits, were modest in scale. Even though he describes himself as a deficit hawk, he didnt insist upon substantially lower spending in the way 2009 conservative Democrats did on the stimulus. Two other relatively conservative Democrat senators, such as Arizonas Kyrsten Sinema and Montanas Jon Tester, demanded even less.

Things could change quickly as the debate moves on to other issues. Manchin and other conservative Democrats might not be such willing partners once the debate isnt about a pandemic relief package, which almost by definition needed to be big and quick to be effective. When the bill up for consideration is about infrastructure, climate change, or simply making some of the new relief measures permanent, its a safe bet that conservative Democrats will be pushing to limit the size of expenditures and making it difficult to raise revenue some of the programs will need.

And then there is the other big, lingering issue the Senate must confront: the filibuster . Democrats passed the American Rescue Plan using the budget reconciliation process, a special legislative track in which Republicans couldnt wield the filibuster, which meant 50 votes was good enough. But reconciliation doesnt work so well with other types of legislation, and it wont work at all with proposals unrelated to the budget a category that includes, for example, a bill to stop GOP-led voter suppression efforts.

Many Democrats favor ending the filibuster altogether. Manchin and Sinema have both said they oppose that. But Manchin has hinted he might be willing to consider modifications, depending on the circumstances. And although he seems determined to maintain some distance from the Democratic brand, he also seems more invested in the success of his party and his partys president than his 2009 counterparts ever were.

Whether Senate Democrats keep passing major legislation will ultimately depend on other factors, too not least among them, whether Biden can remain as popular as he is right now. But with all the good feeling around the COVID relief package, Senate Democrats might just decide that acting swiftly and with little relatively internal dissent is something worth doing again.