"President Obama kicks off what might be called his "Save the Senate" tour this week, heading west to campaign for two embattled Democrats trailing badly against Republican challengers - including Senate Majority Leader Harry Reid of Nevada. With high-profile Democrats already bailing out of re-election campaigns - Sen. Evan Bayh's decision on Monday to drop out of the race in Indiana brings the number of retirees to five - Mr. Obama is putting his popularity and fundraising prowess on the line as he tries to help his party hold the majority in the Senate. (cut) Mr. Obama is aware of...