When CO2 tax drops, gas price follows

When Washington's tax on CO2 emissions dropped significantly last month, I predicted that gas prices would decline compared to neighboring states. I tweeted:

"Well, with such a large decline - 20 cents per gallon - we can see if the gap between Washington and neighboring states like Oregon and Idaho, gets smaller over the next month. It will take some time for prices to filter through the system, so let's all meet back here in a month and see what happened."

It is one month later, and we have seen the gap between Washington and neighboring states fall. According to AAA, one month ago the diffe...