Victims of the Boston bombings and their family members may end up participating in the immigration reform debate in the same way that parents of the children cruelly murdered in Newtown, Conn., contribute to the ongoing debate about gun violence: As impossible-to-ignore witnesses to the urgency of the issues raised by these terrible massacres.

The Boston bombers are legal immigrants. At least one of them is believed to have left and returned to the country in recent years. Their assimilation was assumed. Everyone they knew testifies to surprise and shock that they had become ruthless killers and Islamist fanatics.

We know as well that illegal immigration brings with it enormous problems of crime and violence, from the cartels, from transnational gangs, and increasingly from terrorist organizations.

Last August the State Department's counterterrorism coordinator, Daniel Benjamin, stated the obvious about Hezbollah, for example, when he declared it "a very ambitious group with global reach."

The threats posed by crossborder terrorism could make the Boston bombings and shootouts, as horrific as they were, appear minor.

Which is why the criticisms voiced by Sen. Jeff Sessions, R-Ala., of the recently released draft of immigration reform legislation must be addressed by amendments in the Senate or the bill will fail, if not in the Senate, then certainly in the House.

Sessions articulated these criticisms on my radio show Friday, and the transcript of his remarks is posted at True proponents of immigration reform will welcome amendments on the national security issues, debate them openly and support them.

These amendments will come in three categories, and hopefully GOP leader Mitch McConnell can focus Republican energy behind three specific amendments in these areas.

One amendment must oblige a specific amount of mapped border fencing to be built before any regularization occurs, before a single temporary visa is issued. Specifics on the size and design of the fence must be spelled out so that evasion does not again mark the compliance effort.

A law was passed in the Bush years requiring 700 miles of serious fencing to be built. Exactly 36 miles of real fence has been erected, according to Sessions, with easily crossed or moved vehicle barriers being counted by the Department of Homeland Security in its fencing statistics. No more of that.

A good amendment will authorize, fund, specify location and design, and provide a construction timetable for a high double fence with access roads.

The country built interstate highways. It can build border fencing. It can do so in an amendment. This can be spelled out. It need not wait for a "plan" from the Department of Homeland Security, as the draft bill says. Get the plan now and write it into the law.

Background checks and biometric entry-and-exit processes are the second and third areas for which amendments will be needed, and, as Sessions and other security-minded senators detail these amendments, the proponents of the overall design must get behind them.

Immigration reform is crucial for national security. But it has to be done the right way, and unless it is done that way this effort will collapse even as the misguided push for gun control collapsed last week.

Criticism of the draft law should not lead to outbursts of divisive anger such as President Obama displayed last week but to invitations to come and reason together.

Immigration reform can be accomplished, but only if national security is a priority and not an afterthought, a real precondition of regularization, not a rhetorical flourish of promised plans and commissions that may never hatch or meet.

Washington Examiner Columnist Hugh Hewitt is a law professor at Chapman University Law School and a nationally syndicated radio talk show host who blogs daily at