Only John McCain and a few others have been defending a war that almost all Republicans and many Democrats, including Hillary Clinton and John Kerry, initially supported.
Historically, neither party has always been either hawkish or dovish. Democrats supported the Mexican war; Whigs were against.
Republicans backed Lincoln during the Civil War; many Democrats wanted a compromise peace. Republican supported the Spanish-American War and suppression of the Philippine insurrection; Democrat William Jennings Bryan ran against “imperialism.”
For half a century, Democrats were the party more supportive of military intervention. Democrat Woodrow Wilson, after winning re-election as the man who kept us out of war, called for a declaration of war against Germany six months later. He got it, with 50-some dissents.