The motto offended Christians in the 20th century and atheists in the 21st. The words "In God We Trust" are the most controversial words on a coin. No one is suing the government over the words "E Pluribus Unum" "liberty" or "five cents."
The latest salvo against the motto's numismatic appearance is about to be fired by attorney Michael Newdow, who is seeking plaintiffs for his case. Former cases argued that the motto violated the establishment clause of the constitution. But in the 1970 case, Aranow vs. United States, the Supreme Court upheld the motto because it had "lost through rote repetition any significant religious content." The new case will argue that the law violates the Religious Freedom Restoration Act, which states that religious activity may not be substantially burdened without a compelling governmental interest and laws narrowly tailored to serve that interest. Newdow intends to argue that the government has no compelling interest in placing "In God We Trust" on every coin when most other nations function without it.
For background information about the origin of this motto and why Christians were offended, please go to my: two cent piece article.
More recently, I wrote an article about a debate on the motto between Mitt Romney and Barack Obama. With another presidential election coming up, it will be interesting to see whether "In God We Trust" makes it to the debate.