From the prosecution's opening statements in the Bridgegate trial, we're promised evidence will show and that two people -- David Wildstein and Bill Baroni -- had a conversation with Gov. Chris Christie on Sept. 11, 2013 during which time they talked to the governor about the scheme to close lanes to the George Washington Bridge in a form of retribution against Fort Lee Mayor Mark Sokolich.

Wildstein will likely testify that such a conversation took place, and prosecutor Vikas Khanna's opening statement indicated that, "The evidence will show that Baroni and Wildstein were so committed to their plan to punish Sokolich that during those precious moments they had alone with the governor, they bragged about the fact that there were traffic problems in Fort Lee, and Sokolich was not getting his calls returned."

This directly contradicts what the governor told the people of New Jersey and the world repeatedly but most notably in the "great apology" of Jan. 9, 2014, when he said he "had no knowledge and involvement in this issue, in its planning and its execution."

If the prosecution demonstrates this contention, it marks an important legal milestone -- and if evidence shows that Christie knew about the lane closures, the state legislature should consider charges of impeachment.

Remember, when Wildstein first cut his deal with the prosecution, he claimed "evidence exists" that proves that Christie knew. Thus far, that evidence has not emerged. But even without physical evidence, the accounts of events may be damning enough.

If, in fact, Christie was alerted to the lane closures while they were still ongoing it would make the governor complicit in the fraud, and potentially subject to the federal charges that Baroni and Kelly now face, including conspiracy against civil rights, deprivation of civil rights, wire fraud, and conspiring to "intentionally misapply property of an organization receiving federal benefits." The most serious of those charges -- wire fraud -- carries a maximum 20-year sentence.

But even if the federal government cannot or will not make a case against Christie, impeachment can hold Christie accountable for his alleged misdeeds. According to the state constitution, the decision to impeach Christie belongs solely to the New Jersey Assembly, and that decision must be voted on by a majority of members. Democrats currently hold 52 seats in the 80-member chamber.

The state constitution is vague in terms of the requirements, saying only that "The Governor and all other State officers, while in office and for two years thereafter, shall be liable to impeachment for misdemeanor committed during their respective continuance in office."

According to the constitution, impeachment proceedings originate in the state Assembly, and if the Assembly votes by a simple majority to impeach, it is the job of the Senate to hold the impeachment trial, with state Supreme Court Chief Justice Stuart Rabner presiding over the trial.

State Assembly Speaker Vincent Prieto (D-Hudson) says that "after hearing all of the evidence, we will make a determination" as to whether charges of impeachment should be brought against Christie.

While the federal charges being levied against the Bridgegate defendants carry a heavy burden of proof, if the latest revelations are borne out, Prieto and the state Assembly should consider charges of obstruction of justice.

According to state statute, obstruction of justice means that an individual "purposely obstructs, impairs or perverts the administration of law or other governmental function or prevents or attempts to prevent a public servant from lawfully performing an official function by means of flight, intimidation, force, violence, or physical interference or obstacle, or by means of any independently unlawful act."

In Tuesday's Bridgegate testimony, Fort Lee Police Chief Keith M. Bendul indicated that police and emergency responders -- public servants -- were prevented from performing their public function. If testimony and evidence indicates that Christie knew, the Assembly should levy impeachment charges. And of course, other charges could be warranted depending on the evidences presented.

During a trial, state senators are under oath "truly and impartially to try and determine the charge in question according to the evidence," and two-thirds, or 27 members, of the Senate must agree in order to convict the official. For Christie to be convicted, at least three Republican state senators would be required.

Conviction would remove him from office and ban him from any future public service for the state.

Given this reality, one possibility is that, facing an impeachment trial, Christie might decide to step down rather than risking the stain of impeachment, which could politically -- though not legally -- prevent him from serving in a potential Trump administration cabinet position.

Brigid Callahan Harrison is professor of political science and law at Montclair State University, where she teaches courses in American government. A frequent commentator on state and national politics, she is the author of five books on American politics. Follow her on Twitter @BriCalHar.

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