The de facto presidential candidates for two of Mexico's three big political parties have been told they can give speeches, but can't ask people to vote for them or run campaign ads until March.
The third party hasn't yet chosen its candidate but election officials have said that its nominees can run campaign ads _ for its party primary.
This, one of the de facto candidates said, is unfair because campaigning in the primary won't just be seen by members of that party, but by the general public.
He, meanwhile, must remain silent.
Mexico's odd and strict laws governing electoral campaigning were intended to create strict rules in the wake of hotly contested 2006 presidential voting, which was marred by accusations of illicit support for candidates and a wave of unapproved campaign ads.
But the new regulations are creating new charges of inequity.
Institutional Revolutionary nominee Enrique Pena Nieto and leftist Democratic Revolution Party nominee Andres Manuel Lopez Obrador are both running uncontested and their parties won't be holding primaries.
Mexican electoral law says that official election campaigning cannot begin until March.
This has put the virtual nominees in the strange position of having sewn up their nominations, but having to avoid anything that looks like campaigning.
The ruling conservative National Action Party, however, has not chosen its candidate and the national electoral institute has said its three contenders can campaign for the party nomination until primary season ends in mid-February.
Peno Nieto, who leads in most polls on the presidential race, protested on Tuesday that the ads run during the National Action primary could affect the presidential election.
Pena Nieto's party ruled Mexico without interruption from 1929 to 2000, when it lost the presidential elections.
Lopez Obrador said he would accept the rules.