With the U.S. government on pace to sell a record amount of Treasurys this year to fund a yawning deficit, many economists and investors are asking questions about the dollar's prospects.

Curiosity about the dollar also becomes most keen during the summer travel season. During the past few summers, U.S. travelers to Europe have discovered that the dollar doesn't go very far. This summer, the dollar is holding its ground against the euro, but losing pace just about everywhere else.

For...