First came an armed standoff between Texas lawmen and drug smugglers disguised as Mexican soldiers. Next, federal officials seized a stockpile of heavy-duty weaponry - assault rifles, hand grenades, and improvised explosive devices - along the Rio Grande. Then a Mexican police reporter was critically wounded after intruders fired more than 60 rounds into the newspaper's offices.
These three incidents in as many weeks dramatize the rising violence along the US-Mexico border. Drug traffickers are becoming more brazen and expanding their operations to include smuggling people. Even as President Bush proposes to beef up border security, these attacks are renewing the debate over how best to keep criminals - perhaps even terrorists - from crossing into the United States.
"As long as our law-enforcement resources at the border are primarily occupied with millions of laborers, it will be impossible to intercept the thousands of criminals who are also exploiting our borders," T.J. Bonner, president of the National Border Patrol Council, told a US House subcommittee last week.
Ever since Mexican President Vicente Fox declared war on drug cartels last year, border violence has escalated.
"There has been an over 100 percent increase in the last fiscal year in border violence aimed at our Border Patrol agents, and that ranges from gunshots fired across the border to rocks being thrown, sometimes flaming rocks," said Homeland Security Secretary Michael Chertoff last week.
In this fiscal year, which began Oct. 1, the Border Patrol has recorded 192 assaults against its officers.
Part of the rise in violence stems from increased US law enforcement at the border, which is creating a more desperate drug smuggler, many experts say.
But it also is rising because these drug smugglers are becoming heavily involved in the lucrative people-smuggling business and are using the same violent tactics to evade law enforcement, Mr. Bonner says.
Some observers also worry that these criminal smugglers could team up with terrorists wanting to infiltrate the US.
"There is not only great concern that the drug trade is becoming more aggressive, but that terrorist organizations are seeking to exploit our porous border," said Texas Gov. Rick Perry last week while announcing a new state initiative, dubbed Operation Rio Grande. It involves redirecting equipment and manpower from state agencies to the border.
And while Mr. Bush's proposed budget is a step in the right direction with respect to border security, more is needed, said Governor Perry. He traveled to Washington late last week to add his voice to the chorus of Texas sheriffs already lobbying Congress for help.
Bush's budget calls for a 6 percent increase for the Department of Homeland Security, which would include 1,500 more Border Patrol agents, 6,700 new beds in detention facilities, and a significant increase in the number of cameras, sensors, and surveillance equipment along the border.
But some immigration experts say the boost in Border Patrol agents is a waste of resources without a more comprehensive approach.
"We've overspent on migration control at the border, so continued spending in this area is of declining value. We are getting less bang for our buck," says Marc Rosenblum, a visiting scholar at the Migration Policy Institute in Washington. "We need to look for more effective ways to control immigration and not simply to concentrate more resources at the border."
But where to put those resources - and whether to crack down on all illegal immigrants or focus on the most dangerous ones - remains the subject of intense debate.
Those calling for a general crackdown see a contradiction in the White House's budget plan.
"For five years President Bush has been talking about the war on terrorism. But it's all offense and no defense," says Mark Krikorian, executive director for the Center for Immigration Studies in Washington. "And immigration control is the most important defensive tool in this kind of conflict."
He says the budget makes clear that Bush continues to ignore workplace enforcement, one of the main ways to check people's immigration status from inside the country.
Indeed, his budget proposes to spend $100 million more on a program to let immigrants come in as temporary workers than on forcing employers to verify the immigration status of their workers, Mr. Krikorian says. "You can't let in the Mexican dishwasher and keep out the Saudi suicide bomber. Immigration enforcement needs to be comprehensive."
But others say the terrorist threat is overblown.
"There is a real tendency to conflate immigration and terrorism," says Mr. Rosenblum of the Migration Policy Institute. "But almost all immigrants come here without any dark agenda."
In his view, a temporary-worker program would ease the pressure on the Border Patrol so that law enforcement could spend more time spotting terrorist types.
"Instead of spending billions of dollars busting nannies and gardeners, we ought to be analyzing the ways terrorists actually move," he says.