These days there seems to be an increasing number of calls to impeach President Obama. "Enough is enough of the years of abuse from this president," wrote former vice presidential candidate Sarah Palin in Breitbart News on Tuesday. "It's time to impeach." National Review's Andrew McCarthy is promoting a new book entitled Faithless Execution: Building the Political Case for Obama's Impeachment. In February, the House Judiciary Committee held a hearing on "Enforcing the President's Constitutional Duty to Faithfully Execute the Laws," during which the topic of impeachment came up a number of times. A few Republican lawmakers have discussed the subject publicly.

Given the growing crisis on the southwestern border, in large part the result of Obama's executive actions and inactions, it's likely such calls will continue, and perhaps increase. Which makes this a good time to remember the last time there were growing calls to impeach the president -- in 2006, when Democrats worked themselves into a frenzy over the contemplated impeachment of George W. Bush.

In the fall of '06, Democrats were headed toward a big victory in the midterm elections — the win Bush later referred to as "a thumping." Many Democrats, especially in the House, and most notably Rep. John Conyers, who stood to become chairman of the House Judiciary Committee, had been laying the groundwork for an attempt to impeach the president.

In August of that year, Conyers released a 350-page report entitled "The Constitution in Crisis: The Downing Street Minutes and Deception, Manipulation, Torture, Retribution, and Coverups in the Iraq War, and Illegal Domestic Surveillance." The report featured a long list of Bush actions which Conyers said violated specific U.S. statutes. The laws broken by the president, according to Conyers, included: Committing a Fraud Against the United States (18 U.S.C. 371); Making False Statements to Congress (18 U.S.C. 1001); The War Powers Resolution (Public Law 93-148); Misuse of Government Funds (31 U.S.C. 1301); The Anti-Torture Statute (18 U.S.C. 2340-40A); The War Crimes Act (18 U.S.C. 2441); Obstructing Congress (18 U.S.C. 1505); The Foreign Intelligence Surveillance Act (50 U.S.C. 1801 et seq.); The National Security Act of 1947 (50 U.S.C. chapter 15) and many others.

There was absolutely no doubt Conyers was preparing for impeachment. And he wasn't a back-bencher but the incoming chairman of the Judiciary Committee, in which impeachment proceedings would originate. (Just for good measure, Conyers had a long inclination toward impeachment; back in 1983, he had tried to impeach Ronald Reagan for the invasion of Grenada.)

Conyer's move was met with enthusiastic applause from the activist corners of the Democratic base. Impeachment talk grew as the midterms approached. The talk got so loud that Rep. Nancy Pelosi, who hoped to become Speaker of the House, felt the need to intervene. With the election just days away, Pelosi went on "60 Minutes" and declared: "Impeachment is off the table."

"That's a pledge?" asked CBS’s Lesley Stahl.

"Well, it's a pledge in the — yes, I mean, it's a pledge," Pelosi said. "Of course it is. It is a waste of time."

Democrats went on to win, and impeachment didn't happen.

Now impeachment talk is being heard among Republicans. So far at least, GOP lawmakers have produced nothing like Conyers' 350-page indictment of Bush. But even without such an indictment — and the Republican case against Obama focuses mostly on alleged dereliction of duty, as opposed to the violations ascribed to Bush — it's a real possibility impeachment talk will continue to grow.

The problem is, there is no more plausible case for impeaching Obama than there was for impeaching Bush. It is highly likely that any action involving impeachment would spark serious public opposition and work to the president's benefit. So if impeachment talk becomes louder, it will fall to House Speaker John Boehner -- the man who controls the body in which any impeachment effort would have to begin -- to shut it down.

Maybe Pelosi's heart was with her fellow Democrats who wanted to impeach Bush. But in her party's best interests, Pelosi angered the activist base, frustrating one of her most senior colleagues, and closed off the possibility of impeachment.

Maybe Boehner's heart is with impeachment advocates, too. Certainly some critics have characterized the Speaker's possible lawsuit against Obama as a "dress rehearsal" for impeachment. But the fact is, if the talk about impeachment continues to grow, Boehner, acting in his party's best interests, will have to follow Pelosi's example and declare an end to it.

UPDATE: After this article was posted Wednesday morning, Boehner was asked about Palin's call for impeachment. He answered, "I disagree." The Speaker was then asked about fellow House Republicans who have also called for impeachment, and his answer again was, "I disagree." Will that end the talk? It's not at all clear that Boehner's "I disagree" is as forceful and definitive as "Impeachment is off the table." Asked about Boehner's comment, a spokesman said, "I think his message is pretty clear."