As the House continues its piecemeal approach to immigration reform, the Senate is pushing to pass its comprehensive bill later today or by Friday at the latest. The bill may not get the 70 votes being sought by its proponents to send the House a strong political signal, but it has more than the 60 votes needed to break a potential filibuster.

“The deadline was never July 4th, but rather the end of this week,” a Senate aide said. “We are on track to pass the bill as soon as [Thursday], but will finish one way or another by Friday. We have well over 60 votes for the measure.”

The “Gang of Eight” behind the bill and other supporters may have to pass the 2013 immigration reform bill without swing voter Sen. Rob Portman, who said he will not offer his support unless there are improvements to a measure known as E-Verify, which would institute a system to ensure prospective employees are in the U.S. legally. The Ohio Republican said he believes workplace enforcement is the critical element in this overhaul.

Portman co-sponsored an E-verify measure with Sen. Jon Tester, D-Mont., and wants it included as an amendment to the 2013 comprehensive immigration bill. That bill would implement the system sooner nationwide, strengthens antifraud measures and protect employers who make “good faith” efforts to comply with the law. He said unless there is a strong workplace requirement the main legislation will not pass. Portman and Tester were offered a chance to add their legislation to the “border surge” amendment authored by Republicans John Hoeven and Bob Corker but passed on the offer. Now Portman wants a vote on his measure.

Portman’s support would have been another huge push for the “Gang of Eight,” who wrote the main legislation. He was on a list of candidates considered by former Republican presidential candidate Mitt Romney as a running mate. And, Hoeven himself has said that Portman would have attracted another two or three Republicans to the main reform bill.

The Ohio senator said he and Tester were made an offer but they had to co-sponsor the Hoeven-Corker amendment without a chance to look at it beforehand.

“We chose not to do that -- Sen. Tester and I -- for a very simple reason, which is we wanted to have a debate and a vote on this issue,” Portman said. “We believe, and I’m passionate about this -- as you can tell -- that if we don’t fix the workplace we cannot have an immigration system that works. It’s as simple as that.”

He added that without a separate debate and vote on that issue, there is a diminished chance of sending it over to the House with a strong message and that lawmakers in that chamber will not see the bipartisan efforts behind workplace enforcement. Portman said if his bill was included in the “border surge” amendment, then House members would deduce that it wasn’t about improving workplace enforcement, rather about sending 20,000 more patrol agents to the southern border.

“They would’ve been right. Let’s be honest,” Portman said. “We ask something very simple. We just say, ‘give us the opportunity to have a debate.’ It’s not about us. It’s not about politics. It’s about the substance of the legislation.”

A clearly irate Senate Majority Leader Harry Reid, who was trying to set up votes on 32 amendments, said he was trying to be patient but ended up lashing out at Portman. He questioned the senator’s unusual grandstanding and wondered if he was making an excuse to ultimately not back the reform bill.

“I’ve been very patient today,” Reid said. “But I’ve just about had it on this -- all this pontificating on this amendment. This senator from Ohio was offered to put this in the bill. He turned it down and we’re spending all this time here because he’s been aggrieved in some way? ... I wanted to be quiet here all day, but this is enough. … He said no, I assume, because he wants a big show out here to have a separate vote. … But that’s enough of this. Enough of this.”

Sen. Jeff Sessions, R-Ala., who has been leading the charge against the Senate bill, said the “fair and open” amendment process promised by the “Gang of Eight” ended when cloture was filed on Monday.