Ciudad Juarez has been called "the most dangerous city on earth". Driving in from the US side of the border, it doesn't feel like that. You simply pay $2.25 (£1.54) at the toll-booth, and cross the bridge over the Rio Grande from El Paso, Texas.
Ask the Mexican authorities and they will tell you that this is a major factor fuelling the drug wars raging in cities like Juarez.
They argue the lax border controls make it easier for money and guns to flow south from the US.
It is estimated that at least 90% of the guns used by the Mexican drug trafficking organisations have come from the US.
In an interview with the BBC, the chairman of the US Senate Homeland Security Committee, Joe Lieberman, agreed that the border controls are too lax.
"It's been a fact of life that except for occasional random inspections, the American border authorities do not make exit inspections of people and vehicles when leaving the country. That's got to stop," he said.
According to a New York Times editorial, "a vast arms bazaar is rampant along the four border states, enabled by porous to non-existent American gun laws.
"The hypocrisy grows all too gruesome: The US Justice Department pronounced the Mexican drug cartels "a national security threat" even as American gun dealers along the border were busily arming the cartels' murderous gangs."
There is a political dimension to all this, one of the fierce debates which rages periodically in the US concerns the right to bear arms.
Lucrative trade In Mexico, they would like the US to restrict sales but that is not likely to happen anytime soon.
The bigger issue, however, is that drugs smuggling is a multi-billion dollar business.
Senator Lieberman acknowledges that between $8bn and $24bn in drug profits flow back into Mexico from the US every year.
Drug smuggling is lucrative and the cartels will fight and adapt to maintain their grip on it.
Still, Mexican President Felipe Calderon says he hopes to quell his country's rampant drug violence by the end of his term in 2012, and disputes US fears that his government is losing control of its territory.
The Mexican government says that the violence that killed more than 1,000 people nationwide in the first eight weeks of 2009 is a sign that the cartels are under pressure from military and police operations nationwide, as well as turf wars among themselves.
"To say that Mexico is a failed state is absolutely false," President Calderon said in a recent interview.
"I have not lost any part - any single part - of Mexican territory."
Violence 'peaking' The Mexican Attorney General Eduardo Medina Mora also believes that the increase in violence reflects how the drug cartels are falling apart.
He points out that street prices of cocaine in the US have doubled in the last three years, while purity has dropped by 35%.
Mr Medina Mora predicted that Mexico is "reaching the peak" of the violence.
The government's goal is to make smuggling through Mexico so difficult that the drug gangs are forced to look elsewhere.
That, in many ways, is a crucial point, Mexico is trying to shift the problem, but it does not feel it can end it.
Despite decades of trying to eradicate Latin American drug production and trafficking, illegal narcotics are still getting into US cities.
The levels of violence Colombia experienced in the 1980s for example have been significantly reduced, but the country is still a major producer of cocaine.
As one former security official in Juarez, who preferred not to be named for his own safety, said "trafficking won't stop while a lucrative market exists."
Corruption
Some suggest that decriminalising certain drugs would significantly dent the cartel's profits.
The US, however, shows no sign of being ready for a national debate about decriminalising illegal narcotics.
There is also the issue of corruption in Mexico where decades of rule by one party helped encourage corruption.
Since coming to office in December 2006, President Calderon has been trying to remove corrupt officials across the country.
However huge drug profits allow the cartels to pay off local officials.
The former security official from Juarez said the army must clean up the city, and remove corrupt people from their posts, but: "what I've not heard is anybody ask 'what's next?'" after the officials have been removed.
"What's the plan? How do you keep the new police clean? Let's suppose they get $200 a week so you put the wage up to $400. It won't stop them receiving $10,000 a month from the cartels."
"How do you keep tabs on them?" he asked.
The US and Mexico have vowed to work together on the problem, and say they are making progress.
Both sides must know though that the best solution may in the end be to stop the drugs- related violence.
So far no one's come up with a way of ending the drugs trade itself.
