A month ago, Vilsack was considered the front-runner for the agriculture position, but in late November he told the Des Moines Register that he had not been contacted by Obama and was “no longer” in the running. Yesterday afternoon, reports surfaced that would indeed take the helm at agriculture.

Rumors of his selection drew criticism from Michael Pollan-mold food policy advocates, who argued that his support for ethanol and corn subsidies — Iowa is the country’s largest grower of corn — would get in the way of significant reform of the Department of Agriculture. Apparently addressing concerns that the pragmatic Vilsack might hew to the status quo, Obama said that “as fiercely protective of family farms and the farm economy as he’s been, he’s also forward-looking” on issues of energy and sustainability.

Salazar, accepting the nomination in a cowboy hat and bolo tie, emphasized the importance of faith to his ancestors, who helped found the city of Santa Fe, and said, “Today, as I stand here, I see their faith shining brightly on Barack Obama.” He laid out some of his priorities, which include reducing America’s dependence on foreign oil, improving infrastructure, preserving parks and working with Native American nations.

Salazar’s appointment has been criticized by some liberal Democrats who would have preferred the progressive Rep. Raul Grijalva (D-Ariz.). According to NPR, “The only ones pleased with the rumored pick were those in the agriculture and mining industries. During the campaign these folks, generally, were counted as supporters of Republican John McCain.”

But Obama said that Salazar would be “at the cutting edge of environmental of energy policy so that commercial interests are just one group among many groups.” And liberals may actually stand to gain from his appointment. Salazar, who worked in environmental law before becoming a senator, is considered more progressive on the environment than on other issues. His Senate seat may now be filled by a more liberal legislator.

Once again, Obama could not dodge the Blagojevich scandal when he took questions from reporters. Asked when his report on his team’s interaction with the Illinois governor might be released, he replied that the delay was “a little bit frustrating” to him and assured reporters, “By next week, you guys will have the answers to all your questions.”

Salazar, a centrist first-term senator, will take the helm of a department that was rocked this year by a sex, cocaine and bribery scandal. Cleaning up the bureaucracy at interior will likely be as high a priority as cleaning up the nation’s parks.

Salazar’s selection marks the fourth elevation of a popular Democratic senator to the new administration, after Obama, Vice President-elect Joe Biden and Secretary of State designee Hillary Clinton. Their appointments have all led to controversies over their replacements.

And the removal of yet another beloved senator has caused concern over the Democrats’ prospects in the Senate in years to come. But as Nate Silver argues, now that Colorado has swung blue, this may actually represent an opportunity for Gov. Bill Ritter to replace the moderate Salazar with a liberal more in line with Obama’s progressive agenda. Silver has a nice breakdown of Salazar’s potential successors.

Late this morning, Obama is expected to name Arne Duncan, who heads the Chicago public school system, as his secretary of education. I’ll be blogging on that press conference shortly after noon ET.