Sit on the sidelines：In a position in which one is not actively participating in something, or in other words：observing rather than taking part. If you are on the sidelines in a situation, you watch it happening but are not directly involved and cannot influence it. （置身事外、袖手旁观）
“On the sidelines”这个俚语前面可以用很多动词（Sit, stand, stay,remain,wait…）
E.G.2：Well, if you’d like for her to remain in office, you’ll take my advice and just stay on the sidelines for now.