President Obama may nominate Chuck Hagel as defense secretary Monday

Former Sen. Chuck Hagel is considered frontrunner

WASHINGTON - The Senate's top Republican says he'll need to take a close look at what former Sen. Chuck Hagel -- who is the front-runner to be the next defense secretary -- has said in the past on Israel and Iran.

Sen. Mitch McConnell says that the next Pentagon chief must have a complete understanding of the U.S. relationship with ally Israel and the threat from Iran.

Some of Hagel's former Senate colleagues have questioned his pronouncements on Iraq, Israel and the Middle East. McConnell tells ABC's "This Week" that Hagel "has certainly been outspoken" on certain foreign policy matters.

McConnell says that if Hagel is nominated, he wants to see if the former Nebraska senator's views "make sense for that particular job."

White House aides said the president has not made a final decision on the post and won't until he returns from Hawaii, where he is vacationing with his family. Obama is due back in Washington Sunday morning.