The American people do not trust President Obama. And they do not trust Republican leadership in Congress. And the reason is simple: for far too long, politicians in Washington have not told the truth.

Both President Obama and Republican leadership are pressing trade promotion authority, also known as TPA, or “fast-track.” Nancy Pelosi and Harry Reid both oppose it.

As a general matter, I agree (as did Ronald Reagan) that free trade is good for America; when we open up foreign markets, it helps American farmers, ranchers, and manufacturers.

But TPA in this Congress has become enmeshed in corrupt Washington backroom deal-making, along with serious concerns that it would open up the potential for sweeping changes in our laws that trade agreements typically do not include.

Since the Senate first voted on TPA, there have been two material changes.

First, WikiLeaks subsequently revealed new troubling information regarding the Trade in Services Agreement, or TiSA, one of the trade deals being negotiated by Obama.

Despite the administration’s public assurances that it was not negotiating on immigration, several chapters of the TiSA draft posted online explicitly contained potential changes in federal immigration law. TPA would cover TiSA, and therefore these changes would presumably be subject to fast-track.

When TPA last came up for a vote, both Sen. Jeff Sessions (R-AL) and I introduced amendments that would have barred fast-track treatment for any trade agreement that attempted to impact immigration law. Two other Republican senators objected, and we were both denied votes on our amendments. Instead, the House inserted substantially weaker language in related legislation.

At the time that Sessions and I introduced our amendments, many said our fears were unfounded. But now we have far more reason to be concerned.

Second, TPA’s progress through the House and Senate appears to have been made possible by secret deals between Republican Leadership and the Democrats.

When TPA first came up for a vote in the Senate, it was blocked by a group of senators, led by Maria Cantwell (D-WA) and Lindsey Graham (R-SC), both of whom were conditioning their support on the unrelated objective of reauthorizing the Export-Import Bank.

The Ex-Im Bank is a classic example of corporate welfare. It is cronyism at its worst, with U.S. taxpayers guaranteeing billions of dollars in loans for sketchy buyers in foreign nations. Ex-Im is scheduled to wind down on June 30. But powerful lobbyists in Washington want to keep the money flowing.

After witnessing several senators huddle on the floor the day of the TPA vote, I suspected that to get their votes on TPA, Republican Leadership had promised supporters of Ex-Im a vote to reauthorize the bank before it winds down.

At lunch that day, I asked Majority Leader Mitch McConnell what precise deal had been cut to pass TPA. Visibly irritated, he told me and all my Republican colleagues that there was no deal whatsoever; rather, he simply told them they could use the ordinary rules to offer whatever amendments they wanted on future legislation.

Taking McConnell at his word that there was no deal on Ex-Im, I voted yes on TPA because I believe the U.S. generally benefits from free trade, and without TPA historically there have been no free-trade agreements.

But then the vote went to the House. Nancy Pelosi, to the surprise of many, led House Democrats to oppose TPA en masse. (Technically, they voted against TAA, which was wrapped into the deal on TPA.)

At that point a group of House conservatives went to Speaker Boehner and said they could support TPA if Boehner agreed not to cut a deal with Democrats on Ex-Im, and just let the bank expire.

Boehner declined. Instead, it appears he made the deal with Democrats, presumably tossing in the Ex-Im Bank and also increasing tax penalties on businesses.

Moreover, the Speaker punished conservatives, wrongly stripping Rep. Mark Meadows (R-NC) of his subcommittee chairmanship, and reportedly threatening to strip other conservatives of their chairmanships as well.

Why does Republican Leadership always give in to the Democrats? Why does Leadership always disregard the promises made to the conservative grassroots?

Enough is enough. I cannot vote for TPA unless McConnell and Boehner both commit publicly to allow the Ex-Im Bank to expire—and stay expired. And, Congress must also pass the Cruz-Sessions amendments to TPA to ensure that no trade agreement can try to back-door changes to our immigration laws. Otherwise, I will have no choice but to vote no.

There’s too much corporate welfare, too much cronyism and corrupt dealmaking, by the Washington cartel. For too long, career politicians in both parties have supported government of the lobbyist, by the lobbyist, and for the lobbyist – at the expense of the taxpayers. It’s a time for truth. And a time to honor our commitments to the voters.