One counter argument: national taxes shouldn't be used to produce code that could benefit other countries, unless that is recognised as a kind of international aid.
(Not my opinion, but one I can imagine from certain political quarters)
(Not my opinion, but one I can imagine from certain political quarters)
For example, this is pretty popular political demand here in Germany, as well as in the European Union. (Closely related, almost a special case: that scientific results, especially from public universities, should be open access. And all sources, code as well as collected data, should be openly available.)
It is essentially the same issue as with trading agreements, just a different solution: Instead of waiting for bilateral agreements, here single countries can make a start without having a huge disadvantage.
Doing this efficiently, especially in software with its low replication costs, often means opening your systems for the world to use (fix, improve, buy), but even if not, considering the benefit of others as a detriment to you is almost never optimal -- SW engineering is not a zero sum game.
No, but some stakeholders will see it as such.
Releasing the code (and thus methods) related to that strength would decrease some of those benefits.
I am not trying to comment on the validity of using military and intelligence gathering as tools in national benefit. I do, however, consider the US federal expenditures on military and intelligence gathering as a partial proxy for others' thoughts.
Maybe it'd be better to say that public money should produce public code by default and we'd put the onus on agencies and elected officials to exempt projects from the requirement.
Should the VA publish their record keeping software? Seems sensible. Should we publish the microcontroller code for ICBM guidance systems? I think the status quo of classifying that information is working out well enough.
What matters is that most orgs should make an effort to release as much code as they possibly can.
For example, the tools to access a public API should have an official repository with tools so they are the most complete and up to date.
A positive side-effect of these public projects is finding talent. I've seen it happen that contributors to an open source project will end up working on a EU space agency because they already met other developers and tech being used there.