Read the following passage and then respond to the directions below.

John Doe is at it again. In another one of his liberal, big business schemes, he's after tax-payers' pocket books, trying to convince them that Phoenix needs a rail system. Phoenicians know better. Our freeways and bus system are doing just fine. Since when did Doe regain our trust, anyway? His last idea cost millions and voters had to repeal his proposition to keep the state coffers from being emptied. If Doe is expecting us to forget that, he's as crazy as his idea for light rail. Vote "No" on November 7.

Explain how the argument illustrates the ad hominem fallacy and why that fallacy makes the argument weak.