WASHINGTON — Senate Republican leaders on Wednesday demonstrated the fissures that continue to linger over proposals to overhaul the nation’s immigration laws.

The Senate is largely seen as the chamber that will have to lead efforts to pass any form of legislative change. But the upper chamber’s first hearing on comprehensive immigration reform revealed some Republicans’ strong fears that border security will be left by the wayside in any agreement.

“This is like deja vu for a lot of us,” Senate Minority Whip John Cornyn, R-Texas, said at the hearing of the Senate Judiciary Committee. “I believe that the reason immigration reform failed in 2007 is because the American people don’t actually believe that Congress intends to follow through on important measures like border security, worksite enforcement, visa overstays and the like.”