WASHINGTON – In his long-awaited endorsement of Hillary Clinton, Bernie Sanders’ words were adequate but the music was missing. He used the occasion of a New Hampshire rally for her – in a primary state in which he had routed her – to put his own spin on the Democratic presidential campaign.

Sanders characterized it as the start of “a political revolution to transform America, and that revolution continues.” But there probably is much more hope than prophecy in that declaration.

Sanders can point to modest platform concessions he won from the Clinton camp, but they were relatively easy ones to make, starting with the call for a $15 per hour federal minimum wage. Hillary Clinton had already promised to embrace it eventually. She also went part of the way toward Sanders’ call for free public-college tuition by proposing it for students in families with annual income of no more than $125,000.

In general, Sanders’ endorsement was a no-brainer assured by his avowed determination to keep Donald Trump out of the Oval Office.

If Clinton were to defeat Trump in November, the Sanders movement would face hard going for the next four or eight years of her presidency. Even if the “revolution” lived on, it likely would be led not by the 74-year-old Vermont senator but by someone like his New England neighbor, Massachusetts Sen. Elizabeth Warren.

Sanders, as a member of Congress who ran as a democratic socialist, was never in the party leadership, though he did vote with the Democrats for organizational purposes. Although many in the party are paying lip service to him for his remarkable showing in winning 22 states and 43 percent of the Democratic vote in the primaries this year, it is far from certain that he will have a more influential role when he returns to the Senate.

Losing presidential nominees historically haven’t had much influence thereafter. Only two Democrats, Thomas Jefferson and Andrew Jackson, survived defeat and later won the office. Only one Republican did so, Richard Nixon, as well as only one Whig, William Henry Harrison.

The last time a failed Democratic presidential primary candidate was considered to be in position to have a significant influence in the outcome of an election was in 1968. Then, Sen. Eugene McCarthy of Minnesota surprisingly challenged Democratic President Lyndon Johnson for their party nomination as an outspoken critic of LBJ’s conduct of the Vietnam War.

McCarthy, supported by a small army of college students and dropouts who shared his opposition to the war, jolted Johnson by coming close to upsetting him in that year’s New Hampshire primary.

On the heels of McCarthy’s showing, another Johnson critic on the war, Sen. Robert F. Kennedy, joined the race, whereupon LBJ startled the nation by announcing he would not to seek re-election.

When Kennedy was assassinated in Los Angeles on the night he won the California primary, McCarthy was left to take on Vice President Hubert Humphrey, who had stepped in to replace Johnson and was eventually nominated.

McCarthy, unlike Sanders today, declined to endorse Humphrey, his surviving opponent, until very late in the fall campaign against former Republican Vice President Richard Nixon. Many political analysts concluded that McCarthy’s failure to act sooner cost Humphrey the election.

This time around, Sanders has given Clinton his endorsement well in advance of the election to encourage his very sizeable following among Democratic liberals to vote for her. But, as was the case in the 1968 election, ill will has resulted on the Democratic side from the stiff primary fight.

The Clinton camp, while somewhat buoyed by Sanders’ less than wholehearted backing, must hope that in the end the Trump threat to the Oval Office will turn out a sufficient number of Sanders supporters to vote for Clinton.

Meanwhile, it’s understandable that Bernie Sanders, after his impressive vote and financial support in the primaries, would want a moment of acclaim at the party convention in Philadelphia later this month. But that doesn’t guarantee his optimistic conviction that his progressive revolution “continues” out of the ashes of its 2016 defeat by the party establishment candidate, Hillary Clinton.