From Holden:

Sen. George Voinovich is circulating a letter to his colleagues opposing John Bolton.

The letter from Senator George R. Voinovich was sent to all senators, but it was aimed particularly at fellow Republicans in a chamber in which the party holds a 55-44 majority (with one independent). At least five Republicans would have to join Mr. Voinovich in opposing Mr. Bolton if the nomination were to be defeated.

In the letter, Mr. Voinovich said that while he had been “hesitant to push my views on my colleagues” during his years in the Senate, he felt “compelled to share my deep concerns” about Mr. Bolton’s nomination.

“In these dangerous times, we cannot afford to put at risk our nation’s ability to successfully wage and win the war on terror with a controversial and ineffective ambassador to the United Nations,” Mr. Voinovich wrote. He urged colleagues to “put aside our partisan agenda and let our consciences and our shared commitment to our nation’s best interests guide us.”

Steve Clemons has the full text.