As the 844-page bipartisan Senate immigration bill submits itself to extensive vetting, unexpected policy and political challenges are emerging.

These unforeseen hurdles, beyond the obvious potential tripwires, are not uncommon for large legislative packages that seek to comprehensively overhaul a complete sector of U.S. law. But unanticipated consequences occasionally turn out to be the most difficult to overcome. Washington Examiner columnist Philip Klein sheds light on one such problem that was born of the desire of the Senate “gang of eight” to avoid another issue that might have derailed support for its legislation.

As Klein writes:

“The immigration bill allows those who have been in the country illegally to obtain provisional legal immigrant status — after several preconditions are met — even though they cannot apply for citizenship for at least a decade. But as Jed Graham of Investor’s Business Daily noted last week, because legal residents who are noncitizens are not eligible for the Obamacare subsidies, employers would be able to hire them without offering health insurance and they wouldn’t incur any fines.”

Sen. John McCain, R-Ariz., this week explained the group’s approach to amendments.

“The agreement among the eight of us is, if it’s an amendment to improve the bill … fine. If it’s an amendment that’s designed to kill the bill, then even if we happen to personally agree with it, because our bill is a product of compromise, then we will vote against it,” he said.

The ability of Senate supporters of the bill to manage suggested changes and incorporate them into their original legislation could determine its success once it advances to consideration on the floor. I imagine that supporters of an immigration overhaul in the House will be watching the process closely.