Microsoft is between a rock and a hard place. Google is eating its lunch on the Internet, and big PC vendors like Dell are warming up to Linux. What to do? Sue, Sue, Sue.Microsoft's claim that the Linux kernel violates 42 of its patents while other open source or free programs--including Open Office--infringe on 193 others may, or may not be, valid. No one knows until Microsoft is ready to ID those patents.

As the Free Software Foundation's Eben Moglen told me on Sunday, "What Microsoft has not done is identify specific patents, which is the only thing that, from the point of view of somebody who has been told he's infringing patents, cares about."

Nonetheless, Microsoft's saber rattling is a high risk move--high risk for Microsoft, that is.

If its patent claims are ever shot down in a courtroom, the company will suffer a severe blow to its credibility. If the claims are ruled valid, then what?

Is Microsoft going to sue large, corporate Linux users, most of which also spend millions of dollars per year on Microsoft software, unless they pay royalties?

Is it going to sue Linux distributors and perhaps force some out of the market--a move that would also create chaos for many of its customers who depend on those distributors for Linux support.

Surprisingly, the answer to those questions might be…yes.

What choice does Microsoft have? It's basically lost the Internet to Google. If Linux and other free software continues its march toward mainstream (don't underestimate the significance of Dell's decision to ship Ubuntu Linux for the desktop) what's left for the company?

Only the courtroom.

Which is why CEO Steve Ballmer might steal a line from Johnny Cash to kick off his next big customer meeting: "My name is Sue, how do you do?"