MENDHAM -- Some things are best done under cover of darkness, and for Gov. Chris Christie that includes voting for Republican presidential candidate Donald Trump.

With the sky navy blue and sunrise still a half hour away, the governor who serves as Trump's transition planning chief sped into the parking lot of Mendham Township's Brookside Engine Company to vote for his controversial friend of 14 years.

Polls opened at 6 a.m. sharp, and by 6:06 a.m., Christie was striding past a reporter who asked why he was arriving so unusually early.

"I always vote in the morning," answered the governor, without breaking his stride.

But this was a departure for Christie. For the last seven years, the governor has never voted without first notifying the press of his whereabouts, and taking questions from reporters.

That was not the case this Election Day, which comes just 4 days after the governor's deputy chief of staff and top Port Authority appointee were convicted of conspiracy to misuse the George Washington Bridge's access lanes to exact revenge on the Democratic mayor of Fort Lee.

"Governor Chris Christie and Lt. Governor Kim Guadagno will have no public schedule for November 8," read an email sent to media at 11:23 p.m. on Monday.

Asked again why he voted so unusually early and without notice, Christie answered, "I wanted to vote with Andrew; he's gotta go to work," before darting into a voting booth to the left of his son, who graduated from Princeton in May.

While Christie has vowed support for Trump since February, he left without confirming he'd followed through at the ballot box. But avoiding headlines about the Bridgegate convictions as Christie is plotting Trump's White House appointments is also a top priority for the Trump campaign.

After the guilty verdicts were returned in federal court Friday, Clinton's campaign chairman John Podesta called on Donald Trump to help "drain the swamp" of corruption in Washington by firing Christie as transition planning chief.

After being cleared a second time by FBI director James Comey in a Justice Department probe of her emails, Clinton's projected margin of victory in the popular vote increased to 3.5 percent from 2.9 percent in the past 24 hours, according to statistician Nate Silver's election blog 538.

Christies declined to take a reporter's questions about what role, if any, the governor might take in a Trump administration should the tycoon prevail.

By 6:12 a.m., Christie slipped back inside his SUV, and sped away.

The very first ballot submitted in Mendham this morning was for Trump, and was cast by Mark Ford, a construction developer who narrowly missed the governor's arrival.

An early supporter of U.S. Sen. Marco Rubio, Ford said he'd had cast his vote for Trump because he wanted "to vote for an outsider instead." Asked why, he answered, "Hillary's corrupt."

Claude Brodesser-Akner may be reached at cbrodesser@njadvancemedia.com. Follow him on Twitter @ClaudeBrodesser. Find NJ.com Politics on Facebook.