What's in big defense bill? Plans to avoid another Benghazi, for one.

The National Defense Authorization Act is one of Congress's top priorities. This year's version will change elements of sexual-assault court-martials and put pressure on Afghanistan's president.

If there is one thing Congress does every year, without fail, it is passing the bill that determines how the Pentagon spends its money. Congress might have built its current reputation on missing deadlines, but it has passed the National Defense Authorization Act (NDAA) for 51 consecutive years.

Make it 52. The Senate passed the NDAA late Thursday; the House passed it last week. 

The NDAA will bring some key policy changes to the Pentagon. Here are four of the most noteworthy:

Sexual assault

More than two dozen legislative provisions in the new defense bill are related to handling accusations of sexual assault within the military. Among the most important is one that strips commanders of the authority to dismiss a guilty court-martial finding in a sexual assault case. It would also prohibit commanders from reducing guilty findings to guilty of a lesser offense. Some US military commanders recently did precisely those things, prompting howls of protest on Capitol Hill.

The new NDAA also establishes minimum sentencing guidelines for those charged with sexual assault. Currently, such minimum punishments apply only to the crimes of murder and espionage.

Preventing another Benghazi

Some provisions in the NDAA are aimed at providing clarity on lessons learned from how US officials handled the attack on the US consulate in Benghazi, Libya, in September 2012. The NDAA requires the secretary of Defense, in cooperation with the Joint Chiefs of Staff, to produce a report on the readiness of US troops to respond to a request to support embassy security in the event of a similar attack.

Iran

Although the US is engaged in negotiations with Iran over the extent of its nuclear program, the NDAA forges ahead with threat assessments of the Middle East power. It asks the Pentagon to add detail to its annual Iran Military Power Report. That investigation will now include an assessment of “Iran’s global network of terrorist and criminal groups,” according to a House Armed Services Committee statement, “as well as how such groups operate to support and reinforce Iran’s grand strategy.”

Troops in Afghanistan

Persuading Afghan President Hamid Karzai to sign the Bilateral Security Agreement (BSA), which provides legal protections to US troops deployed to the war zone, is crucial to an ongoing US presence there, lawmakers and top military officials say. To further pressure Mr. Karzai, the NDAA prohibits the distribution of half the funds that US commanders are authorized to give to Afghan officials and communities until the BSA is signed. This includes the Commander’s Emergency Response Program (CERP), which is popular with Afghan communities and has been used to build wells and repair roads.

Because US troops tend to be at particular risk during a withdrawal, when bases are being closed and operations are in flux, the NDAA also calls for a report on the security requirements that commanders will need during that phase of operations.