Here are some pros and cons to Microsoft buying Nokia.

One reason Microsoft should make a bid for Nokia is to prevent someone else from buying it. Nokia's share price has plummeted in the last few years and is now sitting around $6, its lowest point since 1998. All of which makes the Finnish company a relatively cheap and attractive buy.

If another company (say, Apple or Google) stepped in to acquire Nokia, the new owner would surely undo the Windows Phone 7 deal, which would be a devastating blow to Microsoft. And if Microsoft bought Nokia, the deal would force the Finnish company to stay loyal to its new owner.

In addition to questionable loyalty, there's also no guarantee that the struggling Nokia will innovate if Microsoft is merely a partner.