In the last Congress, a Freedom of Choice Act (FOCA) was introduced that would, if brought forward in the same form today, outlaw any 'interference' in providing abortion at will, the bishops said in a statement issued at an annual meeting in Baltimore.
It would deprive the American people in all 50 states of the freedom to enact modest restraints and regulations on the abortion industry, they statement said.
It would also coerce all Americans into subsidizing and promoting abortion with their tax dollars" and "counteract sincere efforts to reduce the number of abortions in our country, they said.
Condemning abortion as a medical procedure that kills, the bishops warned that if FOCA is passed, the unity desired by president-elect Obama and all Americans at this moment of crisis will be impossible to achieve.
Aggressively pro-abortion policies, legislation and executive orders will permanently alienate tens of millions of Americans, the statement warned.
A 1973 Supreme Court decision known as Roe versus Wade legalized abortion on the basis that a woman has a right to privacy under the 14th Amendment to the US constitution.
According to a survey conducted in May by Gallup, roughly 50 percent of Americans are pro-choice for abortion rights and around 40 percent are pro-life opposed to abortion rights.
During the contest for the Democratic Party's nomination, Obama said it was important to protect a woman's right to choose.
And in the closing weeks of the race for the White House, in which abortion took a back seat to issues like the souring economy and the war in Iraq, the Obama campaign ran ads in swing states highlighting the opposition to abortion of the Republican Party presidential ticket of John McCain and the openly pro-life Sarah Palin.