According to everything I can find, MACO was absorbed into Star Fleet when the Federation was created.<br/><br/>The only anomaly is one "Colonel Patrick West", who seems to hold an anomalous rank that doesn't match the uniform he wears.<br/><br/>However...<br/><br/>In the Dominion War, references are made to "Federation Troops". I can find nothing in Memory Alpha other than passing references, such as "Federation troops were beamed down".<br/><br/>There was definitely one episode of DS9 where the Defiant went to the aid of a beleaguered garrison of Federation ground troops.<br/><br/>The fact is that Star Fleet is a navy. Navies are great for protecting supply lines and defending against invasions, and are vital if you wan to carry out an invasion, but the navy itself is not going o be able to do the invasion. You have to have some people who (in the words of Robert Heinlein)<div class="quoteheader"><div class="topslice_quote">Quote</div></div><blockquote class="bbc_standard_quote">...are the boys who will go to a particular place, at H-hour, occupy a designated terrain, stand on it, dig the enemy out of their holes, force them then and there to surrender or die. We're the bloody infantry, the doughboy, the duckfoot, the foot soldier who goes where the enemy is and takes them on in person.</blockquote><div class="quotefooter"><div class="botslice_quote"></div></div>