This would work on load. Not on resize:
if (jQuery(window).innerWidth() < 568) {
jQuery('#boardOfTrustees').masonry({
itemSelector: '.postWrapper',
});
}
To make it work on resize then you would need to use the method destroy
as detailed at the documentation.
$(window).resize(function () {
if (jQuery(window).innerWidth() < 568) {
jQuery('#boardOfTrustees').masonry('destroy');
} else {
jQuery('#boardOfTrustees').masonry({
itemSelector: '.postWrapper',
});
}
});