WASHINGTON — When Senate Democrats in 2013 drastically weakened the ability to filibuster presidential nominees, it seemed as if they were creating a glide path for a president whose party controlled the Senate to speed through confirmations.

But as President Trump and Senate Republicans are learning to their great displeasure, that has not been the case. Instead, a new kind of delaying tactic was born, one meant not to block a particular nominee but to snarl the Senate and limit the number of people who can get confirmation votes.

The barrier, as employed by both parties, is at the heart of an escalating fight over the pace of confirmations and the Trump administration’s ability to fill jobs. With the health care debate temporarily postponed, the focus will now shift to the conflict over nominations.

Because of their 2013 change, Democrats cannot indefinitely block nominees since procedural objections can be overcome with a simple majority vote instead of a supermajority of 60. But they can prolong the process to an excruciating degree and are doing so in many cases, giving Senate Republicans and the White House fits.