While Mexico made great gains in consolidating democracy in 1997 and 2000, these advances risk being severely undermined by doubts surrounding the 2006 election. This article contends that the 2006 pre-electoral environment is, if for different reasons, at least as fragile as that in 2000. If proper measures are not taken to improve electoral playing field transparency and levelness and to help ensure the winner’s selection through a process accepted by all and with broad participation, post-electoral mobilization and short-term ingovernability are possible outcomes. We focus on emerging challenges posed by profligate campaign spending and the lack of disclosure which threaten to delimit the presidential election outcome months ahead of the race. We conclude that greater international attention should be paid to these elections, and suggest that Mexico’s voters and international observers should heed important experimental civil society, media, and academic initiatives to systematically monitor “playing field” levelness.