Sprint Nextel (S) may have realized for a while that it needed to raise its bid for Clearwire (NASDAQ: CLWR) if it stood any chance of getting full control of its networking partner. But you'd better believe that without SoftBank's agreeing to dig a bit deeper into its pockets to bankroll a higher offer, Sprint would probably end up watching some other company get hold of Clearwire's network and valuable spectrum.

With it looking as if Sprint's attempt to buy the shares of Clearwire it didn't already own would have been denied by minority stockholders in a vote that was to be held today, Sprint blinked. It upped its original $2.97-a-share bid 14.5% to $3.40 a share. Clearwire shares had been selling on the open market for well over $3.00 ever since Sprint's offer was made public.

To give itself time to ponder this new offer, the Clearwire board postponed the vote until May 30.

Sprint never would have been able to make its original offer to buy Clearwire for $2.2 billion back in December if not for SoftBank's infusion of $8 billion in cash as a down payment on its Sprint acquisition. But if what SoftBank was really hoping to get in buying Sprint was Clearwire's spectrum, then SoftBank really had no choice but to pay out. As SoftBank CEO Masayoshi Son has said, "[I]n the Sprint-SoftBank transaction, Clearwire's spectrum is the key."

What probably really forced the issue is that master of disruption, the always pesky DISH Network (DISH). DISH had previously made an offer for Clearwire right after Sprint made its proposal. That DISH bid lit a fire under Clearwire stockholders to demand that the Clearwire board hold out for more money.

Crest Financial, with more than 8% of Clearwire shares, and Mount Kellett Capital Management, with more than 7%, had complained bitterly about what they considered a lowball offer. Crest and another investor, Aurelius Capital, even sued the Clearwire board and Sprint over the proposed transaction. Because Sprint was the majority investor with 51% of Clearwire shares, they felt it forced the Clearwire board to accept its bid.

But the new $3.40-a-share offer for Clearwire still may not be enough. Minority shareholders may still decide that Clearwire's spectrum has more value than that.

As the Crest proxy letter to Clearwire shareholders pointed out, "[W]e believe that the value of Clearwire's spectrum increases every day with the advent and development of the TDD-LTE technology that can utilize the same spectrum that Clearwire holds."