WASHINGTON – Democrats have their thumbs on Republican scales in Senate primaries in Missouri and Wisconsin this summer, hoping to improve their own chances of maintaining a majority in November.

The idea isn't quite as far-fetched as it might sound.

Two years ago, Senate Majority Leader Harry Reid's allies invested heavily in an effort to help Sharron Angle win a contested GOP primary in Nevada after deciding she would be the easiest Republican to defeat in the fall. She won the nomination, but ultimately lost to Reid.