The threat of identity theft has been growing ever larger on Americans' radar screens, especially as more and more transactions take place from the privacy of a computer. But last week's revelations that Montana Secretary of State Brad Johnson was victimized should make that blip even bigger.

Johnson tried to use his state-issued credit card to pay for his room this summer while attending a meeting of the Council of State Governments, only to be told the card had been rejected.

As it turned out, someone had used the card's number to run up $17,254 worth of fraudulent charges before US Bank noticed something was wrong and froze the account. The improper charges were removed, and the state didn't have to pay them.

But the mystery remains of how the account number was stolen from the credit card, which Johnson said he had never misplaced or loaned to anyone.

The sad thing is that there are all kinds of ways to be victimized, from an unethical store clerk to a sharp-eyed fellow customer to being duped by a tricky e-mail. The key is to be careful all the time, and the fact that a high elected state official somehow fell victim to identity theft should be another incentive to use caution.