TRENTON, N.J. — Faced with a widening political scandal that threatens to undermine his second term and a possible 2016 presidential run, New Jersey Gov. Chris Christie apologized again Tuesday, saying his administration “let down the people we are entrusted to serve” but that the issue doesn’t define his team or the state.

On the eve of his second term, the governor opened his annual State of the State address by touching only briefly on the apparent political payback plot.

“The last week has certainly tested this administration,” he said. “Mistakes were clearly made. And as a result, we let down the people we are entrusted to serve. I know our citizens deserve better.”

He received tempered applause after he went on, saying, “This administration and this Legislature will not allow the work that needs to be done to improve the people’s lives in Jersey to be delayed.”

His measured tone was a noticeable contrast from a year ago when a blustery Christie promised to lead New Jersey back from Superstorm Sandy, the costliest natural disaster in state history.

The scandal broke wide open last week with the release of documents showing Christie aides and appointees orchestrated lane closings that caused massive gridlock on local roads, delayed emergency vehicles and school buses for hours and infuriated commuters. Democrats believe the scheme was retaliation against a Democratic mayor who did not endorse Christie.

The reception to his ideas from political opponents is likely to unfold as the Legislature gets to work. Democrats may be unwilling to go along with a Republican whom they sense may have been weakened by the scandal.

As Christie left the chamber after his speech, he tersely shook the hand of the Democrat leading one of several investigations into the scandal, which the governor has denied knowledge of and first apologized for last week. He’s also fired a close aide, and others on his team have resigned.

Democrats plan to vote Thursday on continuing their investigation.

“Public safety and abuse of power are the No. 1 issues,” said Vincent Prieto, the incoming speaker of the state Assembly and a Democrat, said after the speech. “We have to get to the bottom to make sure it doesn’t happen again.”

Christie’s State of the State address and inauguration scheduled for next week were intended to launch a second term that’s considered a key building block for his political future. After his November re-election, his advisers suggested he had just a one-year window to stack up accomplishments as a can-do, bipartisan leader before his lame-duck status – and a prospective White House campaign – start to interfere.

The recent revelations may have slammed that window shut. Though he’s not announced plans to run, Christie is an early front-runner for his party’s presidential nomination who now is working to rebound from the scandal, the most serious threat to his administration and political ambitions so far.

Unlike previous years, Christie had no live radio or television appearances scheduled for the day after the annual address.