By Cassandra Garrison
MEXICO CITY (Reuters) -Mexico's ruling bloc appeared to secure the necessary votes to pass a judicial reform bill on Tuesday evening after an opposition senator dramatically broke party ranks to say he would favor the overhaul, which critics fear threatens the rule of law.
The ruling Morena party and its allies had been one seat short of the two-thirds majority needed to pass the constitutional reform that would transform Mexico's judicial system by having judges elected by popular vote.
As boos echoed around the chamber, Miguel Angel Yunes of the opposition PAN party said he would back the reform, breaking the attempt by a severely weakened opposition to block it.
Opposition lawmakers accused the ruling party of underhand tactics to secure the majority, including attempted bribes and the detention of a senator so he could not vote. Morena denied any wrongdoing.
Senators are set to vote later on the reform with debate expected to go into the early hours of Wednesday.
The political drama followed a day of tense debate that was interrupted for a few hours after demonstrators forced their way into the Senate building, marking an escalation of weeks of widespread protest against the reform which has also spooked markets.
Senate President Jose Gerardo Fernandez suspended the session and asked lawmakers to remain calm as demonstrators flooded the upper level of the chamber, chanting "traitors" in opposition to the reform.
The debate will likely go into the early hours of Wednesday morning.
Mexico's major trading partners, the United States and Canada, have warned the changes could undermine the trade pact of the three countries, the USMCA, and negatively impact investment.
The backbone of the constitutional reform, proposed by outgoing President Andres Manuel Lopez Obrador, calls for the election by popular vote of more than 6,500 judges and magistrates, including the Supreme Court.
The reform also proposes reducing the number of Supreme Court justices to nine from 11, shortening their terms to 12 years and cutting required work experience from 10 to five years.
Critics have attacked it as a blatant doubling-down of power by ruling party Morena.
Lopez Obrador and President-elect Claudia Sheinbaum have vigorously defended the reform as essential for holding judges accountable and reducing corruption.