Paul Findley, a moderate Republican congressman from Illinois who sought to limit presidents’ power to wage war and pressed the United States government to engage with the Arab world, died on Friday in Jacksonville, Ill. He was 98 .

The cause was complications of congestive heart failure , his son, Craig, said.

Mr. Findley spent 22 years in Congress. When first elected in 1960 he promised to fight “creeping socialism,” but his views soon moderated and occasionally veered to the liberal side, making him part of a breed of Republicans more common then and almost nonexistent today .

He supported civil rights and, with the blessing of the Republican leadership , named the first black person in the 20th century — 15-year-old Frank Mitchell of Springfield — to the position of page in the House of Representatives.

Mr. Findley was an early critic of the Vietnam War and in 1973 helped write the War Powers Resolution, better known as the War Powers Act , which requires presidents to notify Congress within 48 hours if they send troops into combat. It also limits the time those troops can remain deployed without congressional authorization.