A generally good rule in politics: Don't joke about natural disasters. A couple of politicians at the Republican National Convention have broken it already, underscoring the difficulty of hosting a partisan event in the shadow of natural disaster.

At Sunday's Faith and Freedom Coalition rally, Texas Senate candidate Ted Cruz (R) cracked wise about the tropical storm that's swept through the Caribbean and headed towards the Gulf Coast. 

"We can be thankful for Hurricane Isaac," he said. "If nothing else it kept Joe Biden away." The vice president scrapped plans to rally Democrats in Tampa because of the storm.

"I understand that the Democrats are very sensitive about jokes about Joe Biden, and for good reason," Cruz spokesman John Drogin said in a statement Monday. "As Ted expressed the very same day, it is critical that everyone be fully prepared for any hurricane, and our prayers are with everyone in the path of Tropical Storm Isaac."

Rep. Darrell Issa (R-Calif.) chimed in this morning, suggesting the storm was a preview of November's election.

"Republicans are going to take Washington by storm on Jan. 20 of next year, so if this is the first storm of Republicans taking control of our country again, making America competitive again, I’m fine with that,” he told reporters at breakfast meeting.

Isaac has already left at least 24 people dead and could cause more damage in the U.S.

 UPDATE: Conservatives point out that Democrats are hardly perfect on this issue; former Michigan governor Jennifer Granholm tweeted that the hurricane was a message from God to the GOP.