WASHINGTON — Democrats learned the hard way in 2016 that the right is much more animated by judicial fights after Republicans’ refusal to consider the Supreme Court nomination of Merrick B. Garland helped rally conservative voters behind Donald J. Trump so he could fill a vacancy held open for nearly a year.

Now a new group is emerging on the left in an aggressive effort to counter that imbalance. Demand Justice, a nonprofit being formed by veterans of Capitol Hill, the White House and the Clinton and Obama campaigns, hopes to become a permanent fixture motivating progressive voters on issues related to the federal judiciary while influencing the Senate on judicial nominees.

The organization, which expects to raise $10 million in its first year, is not planning to devote its energy to changing the views of Republicans. It instead wants to instill the same kind of zeal in progressives when it comes to the courts, to make the argument that in the current political environment, it is the federal courts that are the final authority on issues important to progressives such as immigration, abortion, gay rights, social policy, the environment and corporate power, to name a few.

The group will be led by Brian Fallon, the former spokesman for Hillary Clinton who had previously worked at the Justice Department and on Capitol Hill for Senator Chuck Schumer of New York, the Democratic leader. He said he is giving up a role as a television analyst to concentrate on the new push.