JR pass purchased by U.S. Military members?

I will be in japan for less than a month and was wondering if I would still be able to use the JR pass. The problem is that I do not have a passport and will not be able to get one in time for my trip. U.S. military members can travel on their orders and do not need a passport when traveling on official orders. Would this be sufficient enough to receive my pass once I turn in my voucher at a rail station. I just do not want to spend the money for the ticket and not be able to use it. Thank you very much.

If you travel on official orders you are not a tourist.

You can get a JR pass when a foreign tourist visiting Japan from abroad for sightseeing, under the entry status of "temporary visitor

The following people are not eligible to use the Japan Rail Pass:
Japanese nationals (There has been a new eligibility requirements that allow a Japanese national with a certain condition. Please see the section: 2) Japanese people living abroad who meet the following conditions
People who are visiting for non-tourism purposes (working holiday, military, diplomatic, cultural, research, work, etc.)

If you doubt you can contact the company where you will arrange the JR pass. They should help you out also.

What places to visit do you have in your mind?

In the situation which you explain,
the answer is "no" for most rail passes which are issued by one or plural JR companies.

Members of the U.S. armed forces
are not given a Status of Residence under the Japanese immigration control act,
because they are exempt from Japanese laws and regulations on the registration and control of aliens.

Only a few JR passes
seem to be available regardless of Statuses of Residence to foreign travelers.
JR TOKYO Wide Pass, which is issued by JR-East Company, is among them.

- Japan Guide: JR Tokyo Wide Pass
https://www.japan-guide.com/e/e2361_06.html
- JR-East: JR TOKYO Wide Pass
https://www.jreast.co.jp/e/tokyowidepass/

Nearly all JR passes are offered
exclusively to foreign people who stay in Japan under Temporary Visitor Status of Residence.
e.g. Japan Rail Pass, JR-West rail passes, etc.

Unless you are TDY (temporary duty) to Japan, no US military service person would be in Japan for only a month. If you aren't TDY, why don't you use your passport, if you have one, and enter Japan on a Temporary Visitor Status. That will allow you to use a JR Pass.

However, if you're on PCS (permanent change of station) travel and are going to visit Japan before finalizing your change of station and are using your travel orders and military transport to get there, then you're not able to use the pass.

A little more information would be helpful.

Most say you need to be specifically travelling with a tourist visa. So I would assume you are not eligible.

However, don't sweat it too much. They don't save you that much money unless you are making multiple long shinkansen trips in one week.

Without a rail pass, consider air travel. With discount local carriers and advance purchase, you can fly for well under the cost of a train trip between major cities. There is the hassle of airports, though. For more remote areas, bus is often half the cost of rail and often only takes maybe 25% longer to get there.

If you have a travel itinerary mapped out maybe some of us can help you find alternatives or see if the pass would have even saved you money.

You'll be travelling under SOFA rules and with no passport you cannot show the JR staff your temporary visitor status (i.e. the sticker they put in your passport.)