With the Senate Judiciary Committee working into the night on a rewrite of the nation’s immigration laws, here’s a look at the markup so far.

As of 4:30 p.m. Monday, 144 amendments had been considered, with roughly half offered by Democrats and half by Republicans, according to committee staff tabulations.

Chairman Patrick J. Leahy, D-Vt., is highlighting the lengthy committee process and drawing a contrast with prior efforts, including the process undertaken by former Sen. Arlen Specter of Pennsylvania, who chaired the panel as a Republican.

“In 2006, the Republican Chairman circulated his legislative proposal just one week before the Committee met to make opening statements. He then revised his legislation and circulated it barely two days before the Committee met to begin debate and consider amendments,” Leahy said in a statement. “This year, the Judiciary Committee received the bill text on April 17, and after a period of more than three weeks to consider it and draft amendments we began our consideration of amendments to the bill on May 9.”

Leahy is also noting for the record that all 301 of the first-degree amendments were available on the Judiciary Committee website before the markup kicked off. This all seems to be an effort to pre-empt criticism about transparency that could undermine the legislation.

“We have been able to focus our extensive consideration of this complex bill for three weeks and still achieve a fair and transparent process for Committee consideration,” Leahy said. “With the help of the Senators who serve so diligently on the Judiciary Committee from both sides of aisle, I hope by the end of this week that the Committee will have completed its consideration of the legislation and that we will report a comprehensive immigration reform bill to the Senate with the recommendation that it be considered and passed.”

During Monday’s activity, the panel adopted an amendment from Sen. Orrin G. Hatch, R-Utah, to require the use of biometric identification for immigrants exiting the 30 biggest U.S. international airports. Hatch is considered a potential vote in favor of the package drafted by the Senate’s “gang of eight.”

“The amendment adopted today is a good start and I will continue to fight to make the tracking of entries and exits include biometrics in the most effective system we can build when the bill is amended on the Senate floor. If we have an exit system that utilizes biometric information, it will help make sure that future visitors to the United States leave when they are supposed to,” said group member Marco Rubio, R-Fla.

Sen. Jeff Sessions, R-Ala., has been the most persistent skeptic of the bill, speaking more than any other senator to offer amendments and criticism. Sessions held up a report that he said upended claims by supporters of the immigration overhaul regarding biometric exit and entry screening.

“This report is unbelievable in that we didn’t know about it. I am highly offended. This is why the American people are upset about this,” Sessions said. “They don’t trust their government. The IRS can’t be trusted, the Homeland Security writes a report and keeps it secret and nobody knows why, because it rebuts what we’ve been told about an entry/exit visa system.”