Trimming a little.

@@ -25 +25 @@
-<gloss>serving (in, with) (the army, the marines corps, etc.)</gloss>
+<gloss>serving (in the military, congress, etc.)</gloss>

https://jp.voicetube.com/videos/77647/35836221
Served with the United States Marine Corps from 2007 to 2012.
米海兵隊に所属していました。

海兵隊に所属	330	  
海兵隊に所属し	202	  
海兵隊に所属する	117	  

I think I have used "従軍" in the past, but this may be less common.
海兵隊に従軍	98	  
海兵隊に従軍し	63	  
海兵隊に従軍した	25	 

Tatoeaba:
https://ejje.weblio.jp/content/during+the+war,+he+served+in+the+army.
During the war, he served in the army.
戦時中、彼は陸軍に所属していた

https://context.reverso.net/翻訳/英語-日本語/served+in
Most native French agents served in RF.
フランス出身のエージェントは大半がRFセクションに所属していた

https://esta.asia/ESTA-VISA-DS-160-Japanese.php
Have you ever served in the military?
軍隊/自衛隊に所属していたことがありますか？

This has EN/JP versions, which give the following alignments:
https://discovernikkei.org/en/resources/military/19753/
所属・部署 Service branch	Army 
兵役のタイプ Service type	War,peacetime 
所属部隊のタイプ Unit type	Support 
所属部隊 Units served	World War II Army Veteran. Savage 43-07 Served in the 11th Airborne.


https://ja.wikipedia.org/wiki/名誉勲章受章者の一覧
(different gloss: "members")
第442連隊戦闘団第100歩兵大隊に所属する
all-Japanese American 100th Infantry Battalion of the 442nd Regimental Combat Team

海兵隊に所属し、「兵隊神父」（The Grunt Padre）の異名で知られた
who served with the Marine Corps and was known as the Grunt Padre.


https://www.hodinkee.jp/articles/mega-mouse-the-utterly-gigantic-character-watch-collection-of-kerry-lewis
それはケリー・ルイス氏のインスタグラムのフィードで、彼は1969年にキャラクターウォッチの収集を始めた（彼は海兵隊に所属していた）
Earlier today I was asked about wearing a Mickey watch while I served in the military. Here’s the watch I wore throughout my tour while in the USMC….

My grandmother served in WW2, and every time I write about this I wander off to find this gloss again. I think I've used 軍隊 in the past as well, but this term seems a bit more common by n-grams. 

I think this is more about English than Japanese.  Whenever we talk about military affiliation, I think the word "service" is used simply as a sign of respect, and will often be the better gloss. 

"serving (in)" isn't likely to make this any easier to find in the E->J direction (we have 63 glosses for "to serve", and 40 for "serving", and 151 for "service"), so maybe that's a lost cause, but you can only do what you can do.

@@ -24,0 +25 @@
+<gloss>serving (in, with) (the army, the marines corps, etc.)</gloss>

Correct POS order
-*- via bulkupd.py -*-

@@ -18,0 +19 @@
+<pos>&vi;</pos>
@@ -20 +20,0 @@
-<pos>&vi;</pos>

Meikyo vt and vi additions to n,vs entries
-*- via bulkupd.py -*-

@@ -19,0 +20 @@
+<pos>&vi;</pos>