When Senate Democrats invoked the “nuclear option” last week, they immediately did one thing: made this president — and future ones — much more powerful.

Consider: Nominations for executive branch positions — including Cabinet jobs — as well as all non-Supreme Court judicial nominations now need only 51 votes (rather than 60) to end debate and advance to a final vote on confirmation.

Now consider that Senate Democrats control 55 seats. In the past, President Obama would not only need every one of those 55 but also five Republicans willing to cross party lines to force a final, simple majority vote on confirmation.

No more. Obama can now lose as many as five Democrats — with Vice President Biden breaking ties — on virtually any nominee, critical wiggle room that gives him far broader leeway in choosing nominees he wants as opposed to those he believes can win sufficient Republican support in the Senate.

(Sidebar: Dropping the necessary votes from 60 to 50 also allows vulnerable Democrats up in 2014 to oppose the president's picks without doing him any real harm. It’s no accident that of the three Democrats who voted against using the nuclear option, two — Mark Pryor of Arkansas and Joe Manchin III of West Virginia — sit in Republican states.)

The nuclear option means the Senate is about to become a more partisan battleground. (The Washington Post)

To grasp the extent of the change in presidential prerogative that the nuclear option has wrought, consider how different the past year in nominees might look if the current 51-vote threshold had been in place.

Obama made no secret of his desire to install Susan Rice as the next secretary of state following the departure of Hillary Rodham Clinton at the end of 2012. But Rice was seen as a non-starter for the position because of Republicans’ strident opposition to her — most of which was tied to Rice’s comments made after the attacks in Benghazi, Libya, on Sept. 11, 2012. Because Rice could not be confirmed with Democratic votes alone, Obama acceded to political reality and chose then-Sen. John F. Kerry of Massachusetts, who was easily confirmed by his former colleagues.

It’s easy to imagine Obama pushing for Rice under a 51-vote confirmation threshold and essentially daring Republicans to filibuster. They could, of course, do that, but when the Republicans eventually talked themselves out, Obama could have weathered five Democratic defections and still had Rice as his secretary of state.

Or consider the recent debate over whether Obama should pick Larry Summers or Janet Yellen as his nominee to chair the Federal Reserve. Summers was clearly Obama’s favored pick, but several liberal Democrats voiced concerns about his close ties to the banking industry. With Democrats standing in opposition, the idea of Summers winning the 60 votes he needed to get a final confirmation vote was a pipe dream, and the former Treasury secretary removed himself from consideration. Obama chose Yellen, who is now on the fast track.

While opposition from within his party might have doomed Summers’s chances even if he needed only 51 votes for confirmation, it’s plausible that Obama might have been willing to push the Summers nomination forward under the theory that he could bring enough pressure to bear on Democrats to get Summers confirmed.

It’s also possible that if Obama needed only 51 votes for confirmation, he might — emphasis on might because it’s impossible to go back in time — have chosen other people for potentially controversial jobs such as head of the Department of Homeland Security.

Of course, Obama’s power is not absolute. While Republicans, in the minority, have less power than they did a week ago, they retain the ability to slow votes on nominations considerably. Even under the new rules, there can be up to 30 hours of Senate debate on each appeals court and Cabinet-level nominee, while nominees below Cabinet level get eight hours and district court nominees get two hours. Considering that there are 189 executive nominees and 53 judicial nominees awaiting votes, it will remain slow going.

And Obama still can’t afford to totally ignore the wishes and warnings of Senate Democrats because he will need the lion’s share of them to vote with him to confirm future nominees — even under the new rules. (Remember that Harriet Miers, President George W. Bush’s pick for a Supreme Court vacancy in 2005, wasn’t undone by Democratic opposition but rather widespread doubts among Senate Republicans.)

But Obama’s hand — over Senate Republicans but also Senate Democrats — has been significantly strengthened by the passage of the nuclear option. And, assuming the rule stays in place, future presidents have been given far more power to handpick the nominees of their choosing, the Senate — or at least 49 senators — be damned.