The federal government sued the state of Arizona this week over its controversial immigration law, arguing that enforcing immigration laws is a federal responsibility.

And the laughter from Arizona is still echoing across the land.

Of course it’s the federal government’s responsibility to enforce immigration laws. The argument, which we acknowledge may prevail in court, is a laugher in the court of public opinion because it’s undercut by the historic failure of federal lawmakers and successive administrations to enforce immigration laws.

Just last week, President Obama gave a speech in which he said it was essential to move forward with comprehensive immigration reform, yet he only rehashed old ideas without offering a solid plan or timeline.

As we’ve said before, if you’re going to fight to defend your authority, you had better be willing to use it. A lack of faith in the federal government was the foundation for the Arizona law, and other states will follow suit. Politicians in Oklahoma, South Carolina and Utah are pushing for tougher immigration laws when their legislatures return early next year, according to a Washington Post report.

We also found it surprising that the federal government would assert in its lawsuit that the Arizona law would harm people’s civil rights and lead to police harassment of U.S. citizens and foreigners. Given the last-minute changes made to the law, the Obama administration’s claim looks like mere pandering to Latino voters.

While we were initially critical of the law, and would prefer to see comprehensive reform passed on a nation level, Arizona legislators watered it down in the final moments of the legislation process. With the changes, we don’t see it as the civil rights threat that it once was.

According to the law, police still would be able to detain a person on the suspicion that the individual entered the country illegally. But one of the changes says that authorities can only detain suspected illegal immigrants in the process of enforcing another law or ordinance.

Furthermore, the law originally said a person’s legal status could not be investigated “solely” on the basis of race, color or national origin. Lawmakers removed the word “solely” and emphasized that investigators must have reasons other than race or national origin to investigate.

Such modifications to the law should have defused the controversy. But clearly advocates on both sides have ignored the changes in order to further their already hardened opinions on immigration.

However, we do think Attorney General Eric Holder’s concern that Arizona’s law will drive a wedge between police and immigrant communities is well stated. When beat cops are forced to act like immigration cops, it can cause a chilling effect in immigrant communities. It becomes harder to solve crimes when potential witnesses are worried about being deported.

It’s yet another reason why this thorny issue needs to be addressed at the federal level. And soon.