A father and son are now on trial in Oregon for murder in the bombing of a bank, in a bizarre scheme to build a private militia in response to the election of Barack Obama.

SALEM — Bruce Turnidge was so fervent about protecting his right to have guns that he once sought to build and supply his own private militia, prosecutors said. His son, Joshua Turnidge, disdained police officers, calling them thieves and believing them all to be corrupt.

The two talked of bank robbery plots over the years no less than 50 times, a friend told prosecutors. The father had tried years before to raise money to arm a militia, but the men he approached turned him down, prosecutors said.

But it was Barack Obama’s presidential win in November 2008 that finally drove the father and son to put one of their ideas into motion, Marion County Deputy District Attorney Katie Suver said Wednesday. They feared Obama’s election would mean more gun restrictions, she said.

An employee at the Turnidges’ biodiesel business recalled that Joshua Turnidge was “practically frantic” after the election about getting cash to reclaim his pawned guns as soon as he could, Suver said.

Then on Dec. 12, 2008, she said, the Turnidges planted a bomb outside the West Coast Bank in Woodburn. It ended up exploding inside the bank, killing two police officers, critically injuring a third and wounding a bank employee.