Vice President Mike Pence is the calm to Donald Trump's storm, bringing a sedate demeanor and the religious, conservative ballast the men hope will spare them from losing the White House.

Pence has served as a pillar of stability in an administration that has churned through top officials, and a steady campaigner ahead of next week's election.

Over the past four years he has also been a lure for a part of the Republican base dubious of a thrice-married reality TV star from New York.

Trump publicly bellows and tweets controversy that Pence is often called in to smooth over or dial back in private, all while never expressing overt disagreement with the president.

Republicans have characterized it as the work of a loyal deputy, but critics have branded him a servile "sycophant-in-chief" more interested in keeping his job.

A lawyer by training and former radio talk show host who served in Congress for 12 years, Pence was plucked from his post as Indiana's governor by Trump's 2016 campaign.

The 61-year-old brought credibility as a traditional evangelical Christian who could appeal to church-going Americans and farm-belt conservatives.

He's been the yin to the president's yang: where Trump plays the unorthodox outsider, Pence is reserved and courteous; where Trump flouts tradition, Pence is deeply pious.

Born June 7, 1959 in Columbus, Indiana, he grew up idolizing liberal icons like John F Kennedy before veering right in adulthood.

Pence is staunchly anti-abortion and while Indiana's governor he signed into law some of the nation's strictest restrictions on terminating pregnancies.

"I'm  a Christian, a conservative, and a Republican, in that order," Pence has said.

Trump has had three wives and many more girlfriends, but Pence is famous for his self-imposed proscription on being alone with any woman who is not his wife.

"Trump's got the populist nationalists," former Trump aide Steve Bannon told the New Yorker. "But Pence is the base. Without Pence, you don't win."

After taking office, Pence let Trump hold the entire stage. He toiled quietly on important jobs such as liaising with Congress and Republicans, and undertaking significant diplomatic missions.

And he adapted his earlier political stances to Trump's antagonistic approach to trade, diplomatic relations and immigration.

In early trips to Europe and Asia, he set the stage for Trump's policy resets while reassuring allies worried about the president's threats.

Pence has remained a team player over his term, never betraying differences with Trump or promoting himself -- sins that cut short the careers of others in Trump's cabinet.

Earlier this year, there was speculation that Trump -- facing a fierce fight for reelection -- would replace Pence with someone who might excite more voters, such as former UN ambassador Nikki Haley or Secretary of State Mike Pompeo. In the end, the odd couple stuck together, with Trump hailing his number two as "solid as a rock" in August.