Rep. Michele Bachmann (R-Minn.) used Twitter on Sunday night to talk up Delaware's Christine O'Donnell, who is running against Rep. Mike Castle (R-Del.) for the state's Republican Senate nomination.

"@ChristineOD," Bachmann tweeted, "is right on all the issues.. pro-job growth, pro-life, anti cap-and-trade and anti-Obama care! Go Christine!"

O'Donnell replied several hours later.

"@BachmannforMN6 Thanks for your support. It seems that common sense conservative solutions aren't that common anymore. Time to change that," she said.

O'Donnell also received an endorsement from former Alaska Gov. Sarah Palin (R) last Thursday. The primary is Tuesday.