Republican presidential candidate Steve Forbes continues to hammer away at G-O-P frontrunner George W. Bush’s rhetoric on abortion. The magazine publisher’s 1996 campaign focused on abolishing the I-R-S and establishing a 17 percent “flat tax” — but Forbes in 2000 has staked out conservative ground on social issues. In his latest Iowa campaign swing, Forbes accuses rival George Bush of being unwilling to guarantee that the Republican Party’s platform include a call for abolishing abortion on demand.Forbes says Bush is trying to have it both ways — and isn’t putting his heart into the “pro-life” cause.Bush campaign spokesmen Eric Woolson says the Texas Governor is clearly on record as an opponent of abortion. Woolson cites Bush’s approval of the law which requires parental notice when a minor seeks an abortion, as well as measures which made adoption easier.