Mark Hosenball, Warren Strobel - Rival political factions facing each other on the streets of Ukraine have also enlisted heavyweight lobbyists in Washington, some with connections at the highest levels of US government, to promote their causes to American policymakers, media and members of Congress.
Among the high-profile lobbyists registered to represent organizations backing Ukrainian President Viktor Yanukovich's government are prominent Democratic lobbyist Anthony Podesta and former Republican congressional leaders Vin Weber and Billy Tauzin.
Meanwhile, Yanukovich's most prominent political rival, Yulia Tymoshenko, the former prime minister who is serving a seven-year prison term for alleged abuse of power, is represented in Washington by former Democratic Congressman Jim Slattery, a partner in the law firm Wiley Rein LLP.
The sums of money involved are substantial. Over the last two years, the European Centre for a Modern Ukraine, a Brussels-based organization sympathetic to Yanukovich and his political party, has paid $560,000 to Weber's firm, Mercury, and another $900,000 to Podesta Group Inc, for a total outlay of $1.46 million, according to a US Senate database.
The database shows total payments over the same two years of $810,000 to Wiley Rein by Oleksandr Tymoshenko, a Ukrainian businessman and husband of Yulia.
"A lot of people are making a lot of money off Ukraine's political competition," said Bruce Jackson, president of the Project on Transitional Democracies, which advocates Western-oriented reforms in Eastern Europe.
"The Yulia-Yanukovich competition has definitely spilled out of the country. Both sides are heavily invested in representation in Washington," Jackson said. He said he and his group do not lobby.
Yanukovich's decision last month not to sign a trade and cooperation agreement with the European Union sparked mass demonstrations in Kiev that have thrown Ukraine into political crisis.
Those involved in lobbying, or on the receiving end of persuasion efforts, say the pro-Tymoshenko forces have pressed for sanctions on members of the Yanukovich government. Neither Slattery nor Wiley Rein replied to email and telephone messages requesting comment.
The Senate has already approved, by unanimous consent, a resolution sponsored by Senator Dick Durbin, a member of the Senate's Democratic leadership, calling for Tymoshenko's release from prison. A similar resolution is pending in the House.
Congress also is debating resolutions that urge consideration of sanctions in the event of further violence by government authorities against the protesters encamped in Kiev's Independence Square.
Those working for Yanukovich and his political allies say they are fighting sanctions and trying to improve the government's image.
Podesta said in a phone interview that he and his counterparts at Mercury have been contacting US legislators to argue that approving the pro-Tymoshenko measures would only complicate efforts to improve relations between Ukraine and the West, including the European Union.
Podesta, who heads a D.C. lobbying firm bearing his name, is the brother of John Podesta, a veteran Washington hand who is rejoining the White House staff as President Barack Obama's senior adviser. Earlier, John Podesta served as chief of Obama's 2008 transition team and as White House chief of staff under President Bill Clinton.
Anthony Podesta said he had never discussed Ukraine with his brother and will not talk with him about policy matters after he reenters the Obama administration. He said his firm tends to have more contacts with congressional Democrats, while Weber and his firm deal more with congressional Republicans.
But sometimes the lobbyists deal with members of either party, he said.
The source of the lobbying funds from the European Centre for a Modern Ukraine is unclear. In a filing with the European Union, the group listed its budget for the financial year ending in November as 10,000 euros, or about $14,000 - a fraction of the $1.46 million it paid the Washington lobbyists.
The Centre's managing director did not reply to two email inquiries. Sources and previous news reports described the group as tied to Yanukovich's Party of Regions.
Lobbyists in most cases do not have to publicly disclose each instance they meet with executive branch officials or US lawmakers. In filings with Congress, they are required to provide general descriptions of the issues or legislation on which they are lobbying.
Anthony Podesta, Weber and Tauzin, and their firms, all have filed papers with Congress or the Justice Department, or both, registering to represent pro-Yanukovich interests. Tauzin's firm and Weber's firm declined to comment.
Gene Burd, a lawyer with Arnall Golden Gregory, said his and Tauzin's firm had lobbied Capitol Hill - and in a handful of cases, Obama administration officials - on issues similar to those promoted by Podesta and Weber's firms.
Arnall Golden Gregory has registered, in tandem with Tauzin's personal lobbying firm, to represent Dmitry Shpenov, a Ukrainian parliament member representing the Party of the Regions, the filings show.
Several sources knowledgeable about the lobbying efforts said that Tymoshenko's allies have found receptive ears in some corners in Washington and have an advantage in an attractive, charismatic and imprisoned politician.
"I think they were quite effective. They also have a product to sell - a good product," said a congressional aide who has dealt with lobbyists from both sides. The aide requested anonymity to describe behind-the-scenes discussions.
Burd said that since the current crisis over dealings with the European Union had boiled over into sporadic violence on the streets of Kiev, he has not engaged in Washington lobbying. Lobbying by others also appears lately to have been dialed back, the sources knowledgeable with the effort said. –Reuters