After a four-year investigation, the Federal Elections Commission announced a sweeping lawsuit against the group, founded by the television evangelist, Pat Robertson.
The decision is a boost for the Democratic Party and is certain to crimp the sway of the Coalition in this year's presidential elections.
The charges relate to the group's activities in the 1990, 1992 and 1994 congressional and presidential election seasons, which included the distribution of highly partisan voters guides, the holding of conferences and huge mail-shot and telephone-bank operations aimed at voters.
These activities have been branded as illegal by the government because they were not reported to the FEC, which they ought to have been.
And because the Christian Coalition is incorporated, it is also being charged with making unlawful corporate contributions to its chosen candidates.
If it is found guilty, the Coalition could face heavy fines and strict controls on its role in future elections. Ralph Reed, its executive director, recently insisted he was "absolutely and totally confident that we are in full compliance" with election laws.
The Coalition's efforts have always been concentrated on those candidates it believes uphold "family values" and on opposing the right of women to seek abortions. In 1994 it famously championed Colonel North, who rose to fame in the Iran-Contra affair, in his unsuccessful senate bid in Virginia.
Among the FEC's findings are that in 1992 the organisation mailed 28 million voter guides urging support for Mr Bush over President Bill Clinton. In 1990 it allegedly made about 30,000 phone calls to voters in South Carolina to bolster the re-election campaign of Senator Jesse Helms. In the same year up to 10 million voter guides were mailed in seven states "in co-ordination, co-operation, and/or consultation" with the Republican Senatorial Committee, the FEC said.
While the charges are highly embarrassing to Republican Party officials, the high profile of the Christian Coalition and its insistence in opposing abortion has become a major hindrance to Bob Dole in his run at the White House.
He has been making stumbling efforts over recent weeks to play down the abortion issue and paint the picture of a more inclusive Republican party.