"SIGINT Goals for 2012-2016
2.1.2. (S//REL) Counter the challenge of ubiquitous, strong, commercial network encryption
2.1.3. (TS//SI//REL) Counter indigenous cryptographic programs by targeting their industrial bases with all available SIGINT and HUMINT capabilities
2.1.4. (TS//SI//REL) Influence the global commercial encryption market through commercial relationships, HUMINT, and second and third party partners"
It's their mission! Read it how you will, but the hint is pretty strong:
They will undermine, slow, misdirect, block or infect the market to their sole advantage.
There is no limit to their attack, they will apply all available SIGINT and HUMINT capabilities . HUMINT is their terminology for spies & espionage, but we can also presume that black ops, sabotage and cyberwar are on the table. Nor are they shy of using using their captured industrial partners to "influence" the shipping of faulty product.
The attack on NIST was in alignment with these goals, further highlighting that the NSA has no particular qualms in undermining an own-country national champion of standards.
Everyone is a valid target, no limits. This isn't a USA versus the world question, nor an open source versus commercial cryptography skirmish. The questions that remain are these: