THE PERILS OF UNCONTESTED LEADERSHIP
Just think of how recent political history proves the point. Jimmy Carter's disastrous Presidency in the late '70s—with its sky-high unemployment and inflation and off-the-rails economic policies—was made possible by a yes-yes-yes congressional majority. Ultimately, Ronald Reagan was able to right matters, not just by installing Republican policies but by formulating a new approach in conjunction with the feisty Democratic opposition.
Similarly, Bill Clinton's first two years in office weren't nearly as successful as his last six, when Newt Gingrich spearheaded the Republican Party's strong counterpoint to Democratic initiatives. Surely, the sustained prosperity of that era was aided by the thoughtful (read: fierce) debate.
Finally, you need only look at George W. Bush's first six years in power to see the downside of one-party rule. The government spent like drunks at a liquor mart, abandoning fiscal principles and steering us into a difficult war.
The primary cause of the economic maladies in the 1970s was the Organization of Petroleum Exporting Countries (OPEC), which dramatically increased the price of oil through coordinated manipulation of its supplies. Since oil or the energy its helps create is an input in the production of almost every product, this led to significant cost-push inflation. This would have occurred regardless of the political party in power or whether power was shared.
A glance at the annual change in the U.S. public debt since 1940 suggests the abandonment of fiscal responsibility can more easily be blamed on the ascension of supply-side economic doctrines with the election of Ronald Reagan in 1980 and the popularity of tax cuts, rather than the lack of divided government from 2001-2006. Using the Welches´ questionable logic, one could just as easily have argued the opposite point - that divided government is detrimental to the economy. In the recessions of the early 1980s, the White House and Congress were controlled by different parties. The same can be said for the 1990-1991 recession. The 1992 elections when Bill Clinton won the presidency and Democrats gained control of the House and Senate initiated a decade of prosperity and economic growth. So which is it? I think the answer is there is no correlation between economic prosperity and whether the U.S federal government is divided. There are periods of prosperity for both divided and undivided government. The same goes for economic downturns. One can selectively choose data to imply almost anything. And even if the data showed a correlation (which they don´t), that would in no way imply causation.
I happen to agree that it is wise to ALWAYS listen to divergent opinions and to seriously consider them when making policy decisions. Yet, this has little to do with whether government is divided politically. The administration of George W. Bush seemed uninterested in alternative perspectives regardless of whether Congress was controlled by Republicans or Democrats. Colin Powell was asked to leave the Bush cabinet in November 2004 because he frequently disagreed with others in the administration. What matters is the INDIVIDUALS in positions of power and their willingness to seek a broad spectrum of advice.