Rep. Tom Cole knows that offense is often the best defense.

The Oklahoma Republican is on track to derail an executive order that doesn’t even exist yet by inserting prohibitive language into one spending bill after another.

House lawmakers are expected to vote today on an amendment Cole offered to the Energy and water development appropriations bill that would bar the creation of any rule mandating the disclosure of political contributions. If it passes, it will be the third such change the Congressman has made since June.

His amendments are a pre-emptive attack on an executive order the White House is considering that would require federal contractors to disclose money given to third-party groups. And if the language remains in the bills adopted by the Senate, it could prevent President Barack Obama from moving forward.

“It’s a strong statement that you make when the House continues to vote for this on all these bills,” said Steve Waskiewicz, a legislative aide to Cole. “It builds a record that becomes an important bargaining chip.”

Under a draft of the executive order, which was leaked in April, contractors and some of their high-level employees would be required to disclose money given to third-party groups “to ensure an efficient and economical procurement process.” Those contributions would then be made publicly available online.

The leak prompted a political firestorm on Capitol Hill, raising the ire of Republicans concerned that such a rule could suppress contributions to the groups considered pivotal to the party’s success in 2010. Rep. Darrell Issa (R-Calif.), chairman of the Oversight and Government Reform Committee, held a hearing investigating the issue, and lawmakers in both chambers publicly condemned or celebrated the idea.

The administration, however, has remained silent because the order is still under negotiation. It is part of the White House’s ongoing effort to counter the Supreme Court’s Citizens United decision, which removed limitations on corporations’ and unions’ political spending to outside groups.

Cole’s first two amendments, to bills funding the Departments of Defense and Homeland Security — which awarded $367.4 billion and $13.6 billion, respectively, in contracts last year, according to government data — both passed the House with 20 Democratic votes.

Reps. Walter Jones Jr. (N.C.) and Geoff Davis (Ky.) were the only Republicans who voted against the amendment on the defense bill. Jones and Rep. John Shimkus (Ill.) were the lone Republican crossovers on the homeland security amendment.

While government watchdog organizations and a group of small businesses have praised the administration’s push for increased transparency, many House and Senate Republicans — and a growing number of Democrats, including House Minority Whip Steny Hoyer (Md.) — say it would politicize the contracting process, chill free speech and circumvent the wishes of Congress. The would-be order’s opponents point out that the Senate last year rejected the DISCLOSE Act, which would have compelled the disclosure of donations to third-party political groups.

Hoyer, whose district is home to several federal contractors, repeatedly said he’d oppose such an executive order when the draft was circulated earlier this year, but he decided not to vote for Cole’s amendments.

“Mr. Hoyer does not want to pre-empt the executive branch on a policy that does not exist,” said Daniel Reilly, a spokesman for Hoyer.

Cole also persuaded the Appropriations Subcommittee on Financial Services and General Government to incorporate his amendment in the original text of its spending bill, which is likely to come to the House floor next. The Congressman plans to include his language in upcoming spending bills, Waskiewicz said.

Members have also introduced standalone bills intended to counter the order. Sen. Susan Collins (R-Maine) sponsored the measure in her chamber with 21 co-sponsors and inserted the language in the defense authorization bill, which was approved by the Senate Armed Services Committee last month.

The Senate has yet to take any action on the Defense and Homeland Security appropriations bills, so the prospects for Cole’s amendments are not clear. But policy language in spending bills, unlike disagreements over funding levels, typically survives cross-chamber negotiations.