People often complain that politicians don’t tell them the truth.

They are probably right. The truth is often painful, and politicians usually want to sound positive.

The nomination of Chuck Hagel to be Secretary of Defense, now being filibustered by Senate Republicans, is a prime example.

The senators refusing, for the time being, to let the nomination come to a vote, are trying to use their leverage to get President Obama to admit that he failed to take the necessary steps to prevent the killing of Ambassador Chris Stevens in Benghazi, Libya.

The GOP tried without success to force that admission during the presidential campaign and, later, from then Secretary of State Hilary Clinton.

Whatever Obama may have done, nobody wants to state the obvious. Stevens, a person extremely knowledgeable about Libya, put himself in harm’s way.

He should not have been in Benghazi without more protection, but the State Department went along with his decision. Nobody says that the victim had significant responsibility for his fate.

While that’s understandable, it puts Obama in an impossible position, which is right where his opponents want him.

Appointments to the Cabinet almost always are free from the filibuster, and that will ultimately be true for Hagel. If the GOP were to block him, a later Republican president could face the same tactic.

Yet some senators obviously see the opportunity to try to embarrass Obama, even knowing they will eventually let Hagel be confirmed. Of course, they won’t say that.

Some Republican senators, apparently including Maine’s Susan Collins, seem to have it right. They will not support a filibuster no matter what they think of Hagel.

But Collins and others will not support him. Some will say it’s because of his views on Iraq or Israel. But Collins has at least hinted at the truth.

Hagel’s confirmation hearing went badly. He did not generate a sense of confidence about his ability to be a vigorous leader of a large and complex government department.

Even if his personal policy positions don’t really matter and he must follow Obama’s direction, he did not come across as competent. Nobody wants to speak that truth directly, because he will finally be confirmed and serve in the job.

The Hagel confirmation has also produced the reverse of the truth — an outright lie.

U.S. Sen. Ted Cruz, the Texas Republican newly arrived in Congress, has accused Hagel of taking money from North Korea. The senator has no evidence to support his claim.

Cruz wants more financial disclosure by Hagel than has normally been demanded of Cabinet nominees of either party. He does not care that his approach could hamstring GOP appointees in the future.

He says that he has made the charge as a way of forcing Hagel to reveal more of his finances. In other words, Cruz wants Hagel to be forced to disclose more about his income in order to refute his lie. It does not matter that Hagel is innocent of the charge.

This tactic was used in the 1950s by the infamous GOP Sen. Joe McCarthy, who repeatedly lied when he claimed to have a list of Communists in the State Department.

Cruz’s position has come in for strong criticism from members of his own party — including some who oppose Hagel. Many Republican senators are unhappy to see the specter of McCarthy emerge.

In defending Hagel, the Obama administration says he would be ideal for the position because he would be the first Defense Secretary with military experience as an enlisted person.

But Hagel would not be the first enlisted person to head the Defense Department. Four others served as enlisted men, though three were made officers while on active duty and the fourth later became an officer in the Army Reserve. Because they became officers, the White House defended its claim by splitting hairs.

Besides, there is no proof that having served in the enlisted ranks rather than as an officer or not at all makes a person better suited to be Secretary of Defense. Implicit in that claim is the belief that an enlisted person knows better than anybody that “war is hell.”

In the 2012 presidential election, neither Obama nor Mitt Romney had served in the military, much less been an enlisted person. Yet no serious claim was made that either was unsuitable to be commander in chief of the Armed Forces for that reason.

The Hagel affair has more than its share of hidden truths, unfounded assertions and outright lies, which hardly increases public trust in government.

GORDON L. WEIL, of Harpswell, is an author, publisher, consultant and former public official.