TIJUANA, Mexico  With a bingo hall, a dog track and a vast room of slot machines, Casino Caliente has a fair share of shrieks and groans any night of the year. But when a team of heavily armed men dressed in black barged in and ordered everyone to the floor on a Friday night this month, the outbursts rose to an entirely different level.

“Everybody down!” the masked men shouted, adding expletives to make their point and urgently directing their automatic weapons this way and that. Panic filled the bingo hall, for no one knew what was to come next.

Gone are the days when Mexico’s drug war was an abstraction for most people, something they lamented over the morning papers as if it were unfolding far away. Reminders are everywhere, like the radios blasting drug ballads that romanticize the criminals and the giant banners that drug cartels hang from overpasses to recruit killers and threaten rivals.

The Mexico-based traffickers that ship narcotics from South America to the United States are in a pitched battle with President Felipe Calderón’s government, which has sent the army to trouble spots around the country to shut them down. Police agencies, infiltrated by the drug traffickers and lacking training, have not shown themselves to be up to the job. The results have been mixed: there have been huge drug seizures and arrests of some kingpins, but also violent retaliation by the heavily armed traffickers, who have been killing law enforcement officers and many noncombatants as well.