Google has come down hard on paid links. Don't believe me? Just ask sites like washingtonpost, forbes, and many other high profile sites that have just had their page rank reduced by two to four points. Are you still considering hiring that SEO firm that offers "paid text links" or "paid ad buys" as part of their strategy? I hope not.
Google prefers to have sites naturally linking to each other, as natural linking is the more reliable way to ascertain the relative importance of a site. In the past, Google has come down on FFA or "free for all" linking schemes, link exchange schemes, link farms, and appears to discount reciprocal linking (link trades or link swaps). Now their target is paid links.There is one final way to get a gov backlink (or more than one) to your site. This option is to buy gov links. This is probably the most practical choice for most people. One word of warning though: if you decide to do this, you need to be careful who you buy these links from. Buying links of any variety requires your due diligence and this is especially true with gov backlinks.