WASHINGTON — President Obama is set to end his term with dozens fewer lower-court appointments than both Presidents Bill Clinton and George W. Bush achieved in their first four years, and probably with less of a lasting ideological imprint on the judiciary than many liberals had hoped for and conservatives had feared.

Obama’s record stems in part from a decision at the start of his presidency to make judicial nominations a lower political priority, according to documents and interviews with more than a dozen current and former administration officials and court watchers. Senate Republicans also played a role, by delaying even uncontroversial picks who would have been quickly approved in the past.

But a good portion of Obama’s judicial record stems from a deliberate strategy. While Bush quickly nominated a slate of appeals court judges early in his first year — including several outspoken conservatives — Obama moved more slowly and sought relatively moderate jurists who he hoped would not provoke culture wars.

“The White House in that first year did not want to nominate candidates who would generate rancorous disputes over social issues that would further polarize the Senate,’’ said Gregory B. Craig, Obama’s first White House counsel.

Obama has still put a significant stamp on the judiciary, appointing two Supreme Court justices — the same number as Clinton and Bush each did in eight years — and 30 appeals court judges, roughly as many as either did on average per term.

But his impact has been uneven. He has made significant changes to some appeals court circuits — which have the final word on tens of thousands of cases a year — while leaving others untouched.

In US district courts, where trials are held, Obama has appointed just 125 such judges, compared with 170 at a similar point in Clinton’s first term and 162 for Bush.

Obama has also largely shied away from nominating assertive liberals who might stand as ideological counterpoints to some of the assertive conservatives Bush named. Instead, Obama gravitated toward litigators, prosecutors, and sitting district and state judges, especially those who would diversify the bench.

‘‘Obama didn’t assertively put forward progressive candidates who would be the ideological counterweights to some Republican appointees, and yet his choices have been met with relentless obstructionism anyway,’’ said Nan Aron, president of the liberal Alliance for Justice. ‘‘All of this has left Obama with a significantly smaller judicial footprint than he is entitled to.’’