Not so long ago, Democrats were bragging that they could win back the Senate this November -- and it didn't seem like bravado. The party had recruited a bumper crop of candidates who were leading in early polls. Republicans were mired in nasty primary contests. The economic recovery seemed to be stalled. And Senator John Kerry was riding high -- giving Dems a lift even in some traditionally Republican states.Now, those boasts have been replaced by stony silence and white knuckles. The Republican primaries, instead of producing scarred survivors, have mostly created battle-tested warriors with general-election appeal. The economy, while...