In a rare break with President Donald Trump, Vice President Mike Pence sat out Tuesday's high-stakes U.S. Senate race.

While voters in Alabama received pre-recorded messages from Trump supporting embattled Republican candidate Roy Moore, Pence did not voice a word of support for his party's candidate since early November, when several women accused Moore of sexually harassing and assaulting teenagers when he was in his 30s.

Democrat Doug Jones went on to upset Moore in a closely watched and hard-fought contest with national implications.

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Pence's absence from the campaign was made even more stark when former President Barack Obama and former Vice President Joe Biden jumped into the race with robocalls of their own for Moore's opponent, Democrat Doug Jones.

Pence initially expressed support for Moore after he won the state's primary in September, but that changed after the Washington Post published allegations of sexual misconduct against Moore in early November.

Pence's office issued a statement Nov. 9 calling the accusations "disturbing." And while Pence's political action committee has contributed to incumbent GOP candidates across the country, Moore is not among the recipients.

The cold shoulder continued Tuesday, even as voters went to the polls in Alabama.

When asked about Pence's apparent break with Trump, the vice president's spokeswoman, Alyssa Farah, referred IndyStar to her earlier statement: "The vice president found the allegations in the story disturbing and believes, if true, this would disqualify anyone from serving in office."

That's a very different tact from the one Trump is taking in an effort to defend his party's 52-seat majority in the Senate.

In addition to the robocall, Trump has urged his 44.5 million Twitter followers to support Moore and called on voters to get behind the former Alabama judge and conservative firebrand during a rally last week in nearby Florida.

Pence is focusing instead on tax reform and his upcoming international trip to the Middle East. He spent Tuesday on Capitol Hill advocating for tax reform and faces a challenging environment for his overseas trip later this month because of Trump's decision to formally recognize Jerusalem as the capital of Israel last week.

But a busy schedule doesn't fully explain Pence's lack of enthusiasm for a political contest that is so important to his boss. Instead, his silence is likely the result of tension between his conservative position on social issues and his desire to avoid publicly clashing with Trump, said Mike Murphy, a Republican strategist from Indiana and longtime Pence friend.

"Mike Pence is an eminently moral man. He has a very strong moral compass," Murphy said. "Without interfering or stepping on the president’s toes, I think his silence speaks volumes. Mike Pence is a Christian and a husband and a father before he is vice president of the United States, and that role carries with it a standard that is higher than anything he is charged with as vice president."

Moore is running in Alabama's special election to replace former Sen. Jeff Sessions, who left the seat to become Trump's attorney general. Polls close at 7 p.m. in Alabama, or 8 p.m. EST.

Call IndyStar reporter Tony Cook at (317) 444-6081. Follow him on Twitter and Facebook.