In the last week, it's become apparent that FARC and ELN have joined forces to deal with improved government tactics being used against them. FARC is thought to have some 17,000 armed members, and ELN some 4,500. These numbers are probably lower, as the leftist rebels have been under increasing pressure in the last few years, and increasingly unpopular.  Twenty years ago, FARC, ELN and six other leftist groups were united in their effort to establish a communist state in Colombia. But the gradual forming of alliances with drug gangs corrupted the political goals of the leftist groups, leaving FARC and ELN as criminal gangs with a political agenda. ELN, however, has generally stayed away from the drug business and stuck more with being a rebellion. ELN is responsible for most of the attacks on infrastructure (electrical transmission lines, bridges, roads) and maintains itself by extorting money from rural businesses (as "revolutionary taxes") and kidnapping.