Publicly, GOP leaders and operatives are slamming Republican Sen. Arlen Specter for being an “opportunist.” In a scathing statement released soon after the Tuesday announcement that Specter is becoming a Democrat, GOP chairman Michael Steele charged that Specter “only cares about furthering his personal political interests because he knew that he was going to lose a Republican primary due to his left-wing voting record.”

Privately, however, Republicans are grimacing, stunned, angry and thrown off-kilter, by Specter’s defection.

The real issue here is not so much about Arlen Specter but more about what his abrupt departure from the GOP says about the Republican Party and its ever-shrinking political base in American politics.

As a lifelong moderate Republican myself, (who is also a person of color from the Northeast) who has long admired Sen. Specter for being a strong voice of bipartisanship and reason within the otherwise conservative Senate GOP caucus, I am deeply disappointed by Specter’s decision to abandon his party for overtly political reasons. No matter how you slice this, Specter did not leave the GOP on principle as much as he did for political expediency. Frankly, that is beneath someone of his stature and dignity.

Whatever happened to when the going gets tough…? Guess those old adages of loyalty no longer apply in our modern-day politics.

What the GOP needs right now is for solid and sensible Republicans such as Sen. Specter, Chairman Steele, Sen. Olympia Snowe, Sen. Susan Collins, former New Jersey Gov. Christine Whitman, Sen. Kay Bailey Hutchison, Sen. John McCain, Gen. Colin Powell, Rep. Eric Cantor, Gov. Bobby Jindal, former Secretary of State Condoleezza Rice and my good friend Rep. Paul Ryan of Wisconsin to work to bring the GOP back to the center and work with their conservative colleagues to build a new unified GOP coalition dedicated to national security, smaller government and fiscal responsibility. Only when this happens will the GOP become a “big tent” national party.

All Tuesday afternoon, Republicans were calling one another, trying to take stock of the moment. I spoke with one longtime senior GOP state official in Pennsylvania, who told me, “Specter had his moments with the party leadership—we had our ups and downs for sure, but we always worked them out. I can’t say I am surprised, however, at his decision…. He did what was politically necessary to keep his power base in Washington for Pennsylvania.”

TheRepublican Party, according to national news reports, is at its lowest level of party identification and registration since 1983. After the 2008 election, the GOP has been viewed as a contractingregionalparty that is mostly white, Southern, Christian and male. The 2008 election campaign showed the GOP’s weakness in its inability to attract young, black and Hispanic voters as well as voters who live outside of the south and southwest.