Hopes that a House bipartisan working group could help chart a path forward on an immigration overhaul may have been dashed Friday with the announcement that two more House Republicans were walking away from the table.

Texas GOP Reps. Sam Johnson and John Carter said in a joint statement that they decided to leave the “gang of seven” because of “a lack of faith in President [Barack] Obama to enforce the current and new laws necessary to solve the immigration problem.”

“After years of hard work and countless meetings, we have reached a tipping point and can no longer continue working on a broad approach to immigration,”  Johnson and Carter said in their statement. “We want to be clear. The problem is politics. Instead of doing what’s right for America, President Obama time and again has unilaterally disregarded the U.S. Constitution, the letter of the law and bypassed the Congress … in order to advance his political agenda. We will not tolerate it.”

They continue: “If past actions are the best indicators of future behavior; we know that any measure depending on the president’s enforcement will not be faithfully executed. It would be gravely irresponsible to further empower this administration by granting them additional authority or discretion with a new immigration system.”

Carter and Johnson close by saying they “will continue to support efforts from our Republican colleagues” and expressing pride and appreciation for the other members of the working group.

The first Republican to leave the one-time “gang of eight” earlier this year was Rep. Raúl R. Labrador of Idaho, citing irreconcilable differences with the other members.

That now leaves a “gang of five” with one lone Republican: Mario Diaz-Balart of Florida. The Democrats are Caucus Chairman Xavier Becerra and his fellow Californian Zoe Lofgren, Luis V. Gutierrez of Illinois and John Yarmuth of Kentucky.

For months these lawmakers have been working to produce a bipartisan, comprehensive piece of legislation to fix the nation’s broken immigration system, believing that a joint proposal from Democrats and Republicans from disparate backgrounds and perspectives would strike the right chord for their colleagues.

Their plan has been to unveil their proposal as a substitute to the piecemeal approach currently being pursued at the behest of House GOP leadership. But the weeks have ticked by, and with them every deadline the group has set for a grand unrolling of the fruits of their labor.

One Democratic aide familiar with negotiations inside the working group, however, said it was premature to connect a blow to the gang of seven with a blow to the prospects for a comprehensive immigration overhaul.

“I think this is more of a disappointment than a shock,” the aide said. “The group’s demise has been predicted and written about so many times. The window of opportunity was earlier, but they faced headwinds and the vocal minority in the GOP conference was able to reach their crescendo with leadership to try and stop reform.

“This is just a setback,” the aide continued, “but a lot of it depends on the House R’s and their leadership right now.”