Homeland Security Secretary Janet Napolitano announced Friday morning that she is leaving to head the University of California system. Napolitano’s decision comes in the middle of what promises to be a long battle over immigration reform on Capitol Hill — a battle in which she has played a key role. So will her departure change anything?

Unlikely. “Secretary Napolitano’s tenure at the Department of Homeland Security was defined by a consistent disrespect for the rule of law,” said Republican Sen. Jeff Sessions, a top opponent of the Gang of Eight immigration reform bill. “The resignation of Secretary Napolitano should refocus the attention of Congress on its first task: to ensure that the executive branch faithfully carries out the laws of the land. The most significant obstacle to immigration reform remains President Obama’s selective enforcement of the law. Any selection — interim or permanent — to replace Secretary Napolitano must disavow these aggressive non-enforcement directives or there is very little hope for successful immigration reform.”

In the immigration debate, Napolitano became of symbol of what many Republicans saw as the Obama administration’s reluctance to enforce strict border security measures. She became legendary for telling Congress that the U.S.-Mexico border “is as secure now as it has ever been,” which both Republicans and Democrats took as a statement that few, if any, additional border security measures are necessary.

Senate Republicans who opposed the Gang of Eight bill used Napolitano as a one-woman argument for their position that the administration should not be given wide latitude to enforce, or not enforce, security measures included in the bill. Republicans who supported the bill didn’t really deny that; Sen. Marco Rubio, for example, often argued that he would like to see the administration given less discretion as far as enforcement is concerned. But Rubio frequently pointed out that immigration reform is a long-term initiative, while the Obama administration will only be in office for a few more years. He was, in effect, holding out hope that a future Secretary of Homeland Security, or a future president, would take enforcement more seriously.

The problem for Gang of Eight supporters is that Republicans who are skeptical of the bill don’t trust the administration generally, or the president specifically, any more than they trusted Napolitano. And after the experience of the George W. Bush administration, they don’t really trust a future Republican White House to do the job, either. Given that, it’s hard to believe that anyone Obama might nominate as Napolitano’s replacement would really change the immigration argument as it stands now.