Perhaps it is a sign of the times, a symbolic changing of the guard in technology. But Google is on the defensive this morning, explaining its growing power in the technology world and why it must be permitted to continue its aggressive acquisition plans. The chatter started today after Washington Post columnist Steven Pearlstein suggested that it might be time to loosen the search giant's grip.

Pearlstein writes:

There is nothing improper or illegal about Google's monopoly - like Microsoft and IBM before it, it earned that dominance fair and square. And given the dynamic nature of the technology sector, it would probably be counterproductive to prevent Google from using its money and talent to expand into new areas. Where I have a problem, however, is in allowing Google to buy its way into new markets and new technologies, particularly when the firms being bought already have a dominant position in their respective market niches.

That prompted a fascinating response from Google Deputy General Counsel Don Harrison, who writes in a blog post that Google must be permitted to acquire companies in order to stay on the innovation frontier. In the defense, Harrison points to acquisitions by Amazon.com of Zappos.com and Microsoft of aQuantive, and notes that if Google didn't bid for promising companies one of its rivals surely would.

Harrison writes:

Pearlstein expresses concern that Google’s acquisitions preclude the possibility that a company might instead be purchased by Microsoft, Apple, or Facebook. But those companies not only have substantial cash or equity that they use to make acquisitions, they also regularly compete against us and other companies to acquire leading startups. In 2007, Google bought DoubleClick, but then Microsoft spent twice as much for its display ad company aQuantive and Yahoo bought ad exchange Right Media. All mature companies regularly acquire companies to make big bets on new spaces.

The back-and-forth comes as government regulators look into Google's proposed buyout of ITA Software, a leading provider of online travel technologies to Bing Travel, Kayak, Expedia and others. Just this week, Microsoft joined FairSearch.org, a coalition of online travel companies that's attempting to block the sale.

Google has been one of the most acquisitive companies in the high-tech business in recent months.

In the Seattle area this year, Google has acquired Picnik, Jambool, Widevine and Plannr). So, I am sure there are venture capitalists and entrepreneurs who don't want to see the company regulated.

In fact, Google's Harrison points out the importance of M&A to the startup ecosystem in his post.

For startups, getting acquired is often the path to success (especially given the difficult IPO market), so stopping large companies from making acquisitions would only deprive startups of another potential bidder and investors of a potential return on their invested capital. You can’t be both pro-economic growth and anti-acquisitions.

Read Galen Ward's previous guest post on TechFlash: "New Google is the old Microsoft."