The filibuster reforms the U.S. Senate adopted last night are a bitter disappointment to liberal lawmakers and interest groups. They made the mistake of believing the threat by Majority Leader Harry Reid to use the nuclear option and ram through more radical Senate rules with a simple majority of 51 Democrats.

Reid never really wanted to use the nuclear option. He might not have had the support of enough Democrats to make good on his threat, anyway. 

The compromise he agreed to with his counterpart, Republican leader Mitch McConnell, ends the requirement for 60 votes to begin debate on legislation and some presidential nominees. That's good for Democrats, who get to take back some of the power the majority traditionally enjoys in deciding what measures will proceed to the floor, and when. 

In return, Republicans will be allowed at least two amendments once a measure arrives on the floor, ending four years of guerrilla warfare in which Democrats denied Republicans the right to amend bills on the floor and often cut them out of the legislative process on the committee level, too.  

Final passage of legislation and confirmation of nominees will continue to require 60 votes, assuming Republicans continue to invoke their right to filibuster anything and everything. That irritates the Democrats' left wing, which had high hopes that filibusters would become a thing of the past. They had been pressuring Reid to declare that a simple majority of the Senate could end debate on a rule change, and then proceed to change the filibuster rules with 51 of the 55 votes he controls.

Among the rule changes the left sought was a requirement that senators be present at all times on the floor if they wanted to filibuster a bill. Senators can do a silent filibuster -- even from home -- and that won't change with this week's modest reforms. 

Still, the compromise is a smart move on Reid's part. First, the deal contains some underappreciated features. It would reduce the ability of one senator or a small group of senators to stall legislation, which prevents tiny cabals from blocking measures even when they are backed by both party leaders.

Moreover, senators who want to continue debating, even after 60 of them agree to limit debate, must take to the floor and stay there for the rest of the allotted time. Currently, there is no such requirement.

The changes would also ease the confirmation process for some judicial and regulatory agency nominees, including Mary Jo White, the former U.S. attorney whom President Barack Obama just nominated to be Securities and Exchange Commission chairman.

Presidential nominees still need 60 votes for confirmation (or at least five Republican votes, because Democrats now control 55 seats to the Republicans' 45). But nominations can be debated and voted on in a single day. (This shortcut doesn't apply to Cabinet positions or to Supreme Court and appeals court nominees.) 

Finally, Reid is now able to send Senate-passed measures to conference with the House more easily. 

More important than these incremental changes, however, is the morass Reid avoids by not acting unilaterally. If Democrats had changed the Senate's internal rules with just 51 votes, why wouldn't the Republicans do the same to entrench their newfound majority in, say, 2014? 

In truth, no one knows who will be the majority party then, but at some point, Democrats will take the backseat again and Republicans will take the wheel -- and their revenge.  

Enough senior Democrats understood this, and considered the nuclear option a terrible strategy. They agreed with Republicans that using it would run roughshod over more than a century of tradition, in which procedural changes were done only with bipartisan agreement. 

The elder Democrats also rightly worried that ramming changes down Republicans' throats would drive them to retaliate by going on strike. They could also upend any chance of bipartisan cooperation in Obama's second term. 

No doubt, these modest changes won't end the Senate's dysfunction. But if the compromise doesn't produce a smoother-operating Senate, Republicans are on notice that Reid could be back with more reform attempts. He could, for example, try to flip the burden of proof on filibusterers. 

The burden now rests with the majority to stop a filibuster by rounding up 60 votes. This idea would switch that burden to the minority, which would have to prove it has 41 votes to sustain a filibuster at any point, even if it's 3 a.m. Otherwise, a simple majority could shut the talkathon down. Even the Democrats who opposed the nuclear option this time around might agree to adopt this reform down the road.

(Paula Dwyer is a member of the Bloomberg View editorial board. Follow her on Twitter.)