FOX News host Bill O'Reilly dismissed opposition to the Iraq war as “just partisan politics” and declared that “the left” opposed President Bush's decision to invade because “they basically don't like what Bush did because Bush did it.” As evidence, he claimed that "[former President Bill] Clinton bombed the livin' daylights out of Belgrade, and you didn't hear a word of civilian casualties, atrocities, bombs hitting civilians, little kids getting roasted -- from the ACLU or anybody else." The truth is that human rights groups such as Amnesty International and Human Rights Watch vocally criticized NATO in 1999 for allegedly insufficient measures to prevent civilian casualties in Yugoslavia, much as they have done in Iraq. The American Civil Liberties Union (ACLU) has not focused specifically on civilian casualties in either Iraq or Yugoslavia, but in 1999, the ACLU wrote to the Republican leadership in Congress noting that "[m]any members of Congress have already expressed grave reservations ... about putting U.S. ground troops 'in harm's way' in Yugoslavia" and urging them to enforce the controversial War Powers Act to prevent Clinton from sending ground troops to Yugoslavia without congressional approval.

From the February 21 edition of Westwood One's The Radio Factor with Bill O'Reilly:

O'REILLY: Now, the left, they basically don't like what Bush did because Bush did it. If Clinton had done it ... the left wouldn't say anything. So, that's just partisan politics. And I don't know about you, but I've had enough of that.

Later, O'Reilly responded to a caller who challenged this assertion by falsely claiming that during the 1999 NATO action in Yugoslavia, “you didn't hear a word” from groups now opposing Bush in Iraq:

CALLER: Yeah, you're spinning everything to the right. You say things like, “If Clinton had attacked Iraq, the liberals on the left and the ACLU would be all for it.” That's a false premise to make yourself look like who you are.

O'REILLY: And I can back up what I say, but you can't. Clinton was for the war in Iraq. That is on the record, number one. Number two, Clinton bombed the livin' daylights out of Belgrade, and you didn't hear a word of civilian casualties, atrocities, bombs hitting civilians, little kids getting roasted -- from the ACLU or anybody else. See, you're a Kool-Aid drinker, [caller]. All right, so you had a big long straw there in North Hollywood and you take a big sip -- 'cause you don't know what you're talkin' about 'cause you don't wanna know what you're talkin' about. And anybody with whom you disagree, you wanna demonize 'em and put 'em in a little jar because you don't have an argument to counter it. I could destroy you 15 different ways in a debate, and you know it.

On April 23, 1999, Amnesty International "expressed grave concern at the attack in the early hours of 23 April on the headquarters of Serbian state television in Belgrade, during which up to 15 people, all of them apparently civilians, are said to have been killed." On May 11, 2004, the group announced that it had written to NATO "expressing deep concern about the attacks carried out on 7 and 8 May by aircraft under NATO command in which 18 civilians are reported to have been killed." In July 2000, Amnesty released a comprehensive report on Operation Allied Force, which concluded that “NATO forces violated the laws of war leading to cases of unlawful killing of civilians.”

Similarly, on April 7, 1999, Human Rights Watch (HRW) "called for an immediate investigation into Monday's bombing of Aleksinac village, which reportedly killed five civilians and injured fifty." The press release quoted Holly Cartner, executive director of HRW's Europe and Central Asia division, as saying: “The countries of the NATO alliance must take all steps to minimize civilian casualties in times of war.” And in May 1999, HRW “condemned NATO's use of cluster bombs in the air campaign against the Federal Republic of Yugoslavia.” Joost Hiltermann, then-executive director of the arms division of HRW, noted that “The duds that are left inside cluster bombs effectively turn into landmines. And like antipersonnel landmines, they kill civilians even years after the conflict has ended.”

The ACLU has highlighted and criticized interrogation policies and practices in Iraq and Afghanistan that the group believes violates domestic and international law, but the group has not focused on civilian deaths in combat operations. During Operation Allied Force, however, the group strongly challenged the Clinton administration's legal authority to wage war, suggesting that the group was hardly engaging in “partisan politics” on behalf of “the left.” On April 30, 1999, the group sent letters to then-Senate Majority Leader Trent Lott (R-MS) and Speaker of the House Dennis Hastert (R-IL) “to urge that you insist on strict compliance with the Constitution in connection with the commitment of U.S. troops in Kosovo, Yugoslavia and surrounding areas.” Both letters noted that “the Clinton Administration is considering committing U.S. ground forces to the conflict in Yugoslavia” but that "[m]any members of Congress have already expressed grave reservations about the wisdom of the air war currently underway, and about putting U.S. ground troops 'in harm's way' in Yugoslavia." Most of the members of Congress who opposed Clinton's efforts in Yugoslavia were Republicans; 39 of the 41 senators who opposed a resolution authorizing Clinton to conduct air and missile strike operations against Yugoslavia were Republicans. In the House, 200 of the 213 representatives who voted against the resolution were Republicans.

Finally, the letters reminded Lott and Hastert of the War Powers Act of 1973, which limits presidential power to “introduce United States Armed Forces into hostilities” for more than 60 days without congressional authorization. But this act is highly controversial: every president since its passage has willfully ignored the act, claiming that Article II of the Constitution, which declares the president commander in chief of the military and grants the president sole authority to order the military into combat. During NATO's bombing campaign, 31 lawmakers, 27 of them Republicans, filed a lawsuit claiming that Clinton's air strikes on Yugoslavia violated the act and asking a judge to declare the strikes unlawful. A federal judge ruled that the lawmakers lacked standing to sue, and the U.S. Supreme Court declined to hear the case.